FAQ - Holley 670 TB - ALLGOHERE
02-13-2002, 12:32 AM
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I Called Holley, valuable TBI Info!
This might be some good info for some of you, and some of you may already know this stuff. Any input is appreciated. I called Holley tech today, and learned a few things to share with all you 350 TBI, and soon to be 350 TBI guys:
1.) The newest models of the Holley replacent TBI's have different injectors than the older ones had. They went to a Delphi injector that is more stable under higher fuel pressure. They are able to retain the desirable fan shaped pulse without drips.
2.) The 502-6 (GM stock replacement Holley TBI) has 65pph injectors, and a adjustable pressure regulator up to 21psi.
3.) These injectors under the max fuel pressure will flow approx the same as 90pph injectors under normal pressure.
4.) The GM injector pod will not fit the Holley TBI housing, and all Holley injectors are proprietary, except the 69pph, and the 90pph used in the one barrel, smaller cfm models. These two appear to be identical to GM injectors, but Holley wouldn't tell me for sure if they would swap in a GM TBI.
5.) The reason that the 502-6 is listed to fit only 1987-89 TBI vehicles, is the fact that the GM Throttle position sensor changed for 1990-95 models.
6.) They only recommend the 670cfm TBI for use in motors up to 275hp. Although I did mention to the guy that there were people with the 330hp GM crate engine running it.
7.) The 502-6 isn't availible with the 85pph Holley injectors, and the 670cfm model that has the 85pph isn't OEM direct bolt-on like the 65pph 670cfm is. Also, the Housing isn't availible with no injector pod or injectors for less money. you have to but the whole thing already assymbled.
By the time I got off the phone, they had me almost convinced that I couldn't use any of their products to do what I wanted to do. That is, have a HP TBI system to feed a 375hp engine to 5800rpms. The guy was really pushing a company named Howell EFI engineering on me. He gave me supposed Howell part number for a HP TBI kit they make to convert OEM style TBI to support modified TBI engines 300-450hp. It sounded awesome, but when I went to the Howell-efi.com website, I didn't exactly see what he described, nor that part number. I am going to call them soon though. After talking to Holley though, I think I have made up my mind not to use the 670cfm, unless some of you who have it can reassure me. I am going to run a 454 TBI with the stock GM 75pph big block injectors, and the turbocity.com adjustable Fpr(9-13psi i think?). I figure if the 65pph were that flexible to get 90pph, I can get 85pph from the 454 injectors if I raise the pressure. Hopefully this shot-in-the-dark combo will feed my motor what it needs. Check out turbocity.com if you have not, they have some great O.E. replacement direct bolt on high performance TBI mods, so it goes to show Holley isn't the only hope. Thanks for reading fellas, and sorry this post was so darn long.
P.S.... Remember that I don't take responsibility if any of this info is incorrect, I'm simply stating what I learned from Holley.
1.) The newest models of the Holley replacent TBI's have different injectors than the older ones had. They went to a Delphi injector that is more stable under higher fuel pressure. They are able to retain the desirable fan shaped pulse without drips.
2.) The 502-6 (GM stock replacement Holley TBI) has 65pph injectors, and a adjustable pressure regulator up to 21psi.
3.) These injectors under the max fuel pressure will flow approx the same as 90pph injectors under normal pressure.
4.) The GM injector pod will not fit the Holley TBI housing, and all Holley injectors are proprietary, except the 69pph, and the 90pph used in the one barrel, smaller cfm models. These two appear to be identical to GM injectors, but Holley wouldn't tell me for sure if they would swap in a GM TBI.
5.) The reason that the 502-6 is listed to fit only 1987-89 TBI vehicles, is the fact that the GM Throttle position sensor changed for 1990-95 models.
6.) They only recommend the 670cfm TBI for use in motors up to 275hp. Although I did mention to the guy that there were people with the 330hp GM crate engine running it.
7.) The 502-6 isn't availible with the 85pph Holley injectors, and the 670cfm model that has the 85pph isn't OEM direct bolt-on like the 65pph 670cfm is. Also, the Housing isn't availible with no injector pod or injectors for less money. you have to but the whole thing already assymbled.
By the time I got off the phone, they had me almost convinced that I couldn't use any of their products to do what I wanted to do. That is, have a HP TBI system to feed a 375hp engine to 5800rpms. The guy was really pushing a company named Howell EFI engineering on me. He gave me supposed Howell part number for a HP TBI kit they make to convert OEM style TBI to support modified TBI engines 300-450hp. It sounded awesome, but when I went to the Howell-efi.com website, I didn't exactly see what he described, nor that part number. I am going to call them soon though. After talking to Holley though, I think I have made up my mind not to use the 670cfm, unless some of you who have it can reassure me. I am going to run a 454 TBI with the stock GM 75pph big block injectors, and the turbocity.com adjustable Fpr(9-13psi i think?). I figure if the 65pph were that flexible to get 90pph, I can get 85pph from the 454 injectors if I raise the pressure. Hopefully this shot-in-the-dark combo will feed my motor what it needs. Check out turbocity.com if you have not, they have some great O.E. replacement direct bolt on high performance TBI mods, so it goes to show Holley isn't the only hope. Thanks for reading fellas, and sorry this post was so darn long.
P.S.... Remember that I don't take responsibility if any of this info is incorrect, I'm simply stating what I learned from Holley.
02-13-2002, 02:03 AM
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
That all sounds about right.
That's pretty much what they told me last year when I emailed them about using it on my 350 that I'm gonna put in my car.
Except the Howell part. They never said anything about that. But they seemed very determined to make sure I didn't buy their TB. I thought it was kinda wierd.
AJ
That's pretty much what they told me last year when I emailed them about using it on my 350 that I'm gonna put in my car.
Except the Howell part. They never said anything about that. But they seemed very determined to make sure I didn't buy their TB. I thought it was kinda wierd.
AJ
02-13-2002, 02:57 AM
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LOL!
Well, here we are again at the TBI subject. Guys, get the TBI. I love it and it works wonderful! They don't recommend it for
F-Body cars because it was designed for trucks.
*Sigh*
I have a 502-6 and a Weiand 300-49 intake manifold to match.
Not a single problem there! If you want to talk to an expert at this: JPrevost is the person to talk to.
Take a look at my car while you're at it.
http://www.lvfbody.com/whoismember.asp?memberID=101
There are some pictures there too.
The person to really talk to is Jon Prevost. I was nervous about the 502-6 as well. I have no doubt now it will be more than enough. I did have to get a higher hood for the manifold and TBI unit to fit. Maybe that is why they discourage it so much! I have no doubt in my mind that TBI could handle an engine well over 350 HP!
I've had no problems at all. Why does Holley do this? I guess their staff does not recommend application of the unit on what it's not designed for! If that were the case with everything I did, I guess I would have a stock system and forget it.
That TBI is a blessing.
Taking my car to a dealership, the mechanic looked under the hood and said "I'm not touching that thing with a 10 foot pole!" And suggested I take it to some hot rod shop.
I just laughed and laughed and laughed and laughed and laughed.
Up to you. I'm telling you right now I'm happy with it.
F-Body cars because it was designed for trucks.
*Sigh*
I have a 502-6 and a Weiand 300-49 intake manifold to match.
Not a single problem there! If you want to talk to an expert at this: JPrevost is the person to talk to.
Take a look at my car while you're at it.
http://www.lvfbody.com/whoismember.asp?memberID=101
There are some pictures there too.
The person to really talk to is Jon Prevost. I was nervous about the 502-6 as well. I have no doubt now it will be more than enough. I did have to get a higher hood for the manifold and TBI unit to fit. Maybe that is why they discourage it so much! I have no doubt in my mind that TBI could handle an engine well over 350 HP!
I've had no problems at all. Why does Holley do this? I guess their staff does not recommend application of the unit on what it's not designed for! If that were the case with everything I did, I guess I would have a stock system and forget it.
That TBI is a blessing.
Taking my car to a dealership, the mechanic looked under the hood and said "I'm not touching that thing with a 10 foot pole!" And suggested I take it to some hot rod shop.
I just laughed and laughed and laughed and laughed and laughed.
Up to you. I'm telling you right now I'm happy with it.
02-13-2002, 08:31 AM
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so what did you do about the TPS issue? does someone make an adapter? Also, waht fuel pressure do you run? Finally, is the reason you got a taller hood because of the 300-49, or the 502-6? I don't want a taller hood, so if I go with a TBI setup, I will use a perfomer TBI intake bored to 2 inches. Thanks again!
02-13-2002, 09:48 AM
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It's the 300-49
The 300-49 intake manifold is the culprit. Yes your stock hood will fit with a 300-49 intake manifold UNLESS you want to hook up your EGR valve. That was the problem I had. I needed to put in a 1" TBI spacer to raise the TBI unit enough so it would not hit the TBI unit. Once that happened, I could not shut the hood. One thing I could have done is probably gone with a 2" element instead of the 3" element I have.
As far as the TPS connector, you can get one from an auto parts store. Just say you have a truck and you need the part. I was lucky, there was one right in the toolbox! If you can't find one, look around in junkyards and TBI's off GM trucks. It is orange and impossible to miss!
The TBI unit is actually about the same dimensions as the Rochester model. It can bolt to the stock manifold too, for Holley does provide a small adapter that lets you go into your stock manifold... (Why? I don't know why anyone would, but it's provided!)
If you plan on not connecting the EGR valve, no problem. If you do, you might want to consider a lower element on your air cleaner.
-Snowdog
PS...
Stock fuel pressure. Expect it to run a little rich.
Which is exactly what you want! If you want it to run more lean, there is an adjustment on the TBI itself. I had to drill out the little metal cap and use a nail to remove it, then turn it about 720 degrees. Believe me, it is set from the factory at the richest setting when you get it! (Holley, remember?)
There is no adaptor. You have to cut off the round connector. Save it and attach it to the Rochester just in case you want to sell it or something.
As far as the TPS connector, you can get one from an auto parts store. Just say you have a truck and you need the part. I was lucky, there was one right in the toolbox! If you can't find one, look around in junkyards and TBI's off GM trucks. It is orange and impossible to miss!
The TBI unit is actually about the same dimensions as the Rochester model. It can bolt to the stock manifold too, for Holley does provide a small adapter that lets you go into your stock manifold... (Why? I don't know why anyone would, but it's provided!)
If you plan on not connecting the EGR valve, no problem. If you do, you might want to consider a lower element on your air cleaner.
-Snowdog
PS...
Stock fuel pressure. Expect it to run a little rich.
Which is exactly what you want! If you want it to run more lean, there is an adjustment on the TBI itself. I had to drill out the little metal cap and use a nail to remove it, then turn it about 720 degrees. Believe me, it is set from the factory at the richest setting when you get it! (Holley, remember?)There is no adaptor. You have to cut off the round connector. Save it and attach it to the Rochester just in case you want to sell it or something.
Last edited by Snowdog 91 Formula; 02-13-2002 at 04:11 PM.
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02-13-2002, 10:10 AM
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Cruise Bracket!
Cruise control!!!!
I almost forgot about that! If you have cruise, you will need to save the bracket for the cruise control and have a friend or yourself weld it to the holley bracket. You will need to have it about 1" back from the connectors on the throttle. No problem. Cut the cruise bracket at the bend. You will know what I am talking about if you have cruise.
Weld it back to it's former position! I should take some pictures of it. As a matter of fact I should take pictures of the engine compartment. I'll need to borrow my friends cam, so it might be about a week because he is always never home!
I'll let you know when they are posted.
I almost forgot about that! If you have cruise, you will need to save the bracket for the cruise control and have a friend or yourself weld it to the holley bracket. You will need to have it about 1" back from the connectors on the throttle. No problem. Cut the cruise bracket at the bend. You will know what I am talking about if you have cruise.
Weld it back to it's former position! I should take some pictures of it. As a matter of fact I should take pictures of the engine compartment. I'll need to borrow my friends cam, so it might be about a week because he is always never home!
I'll let you know when they are posted.
02-13-2002, 11:07 AM
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Car: RS
Engine: LS1
Transmission: T56
Axle/Gears: 9" for the ladies
The 670 TBI IMHO can't flow enough air to fed much over 275-300HP UNLESS you can make that HP under 4200RPMS.
Most engines arent going to do that without AFR heads and similiar top of the line products. My engine redlines at 5500RPMS.
Like TPI it doesn't pull hard to there.
I think I need a 4bbl TBI as this 670tbi is running into problems getting below 14.00 second 1/4 mile times.
Most engines arent going to do that without AFR heads and similiar top of the line products. My engine redlines at 5500RPMS.
Like TPI it doesn't pull hard to there.
I think I need a 4bbl TBI as this 670tbi is running into problems getting below 14.00 second 1/4 mile times.
02-13-2002, 11:28 AM
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you should read my post 'super L03 7000RPM's' I thought that was true to, but on my 305 that is currently in the car, I have the stock GM TBI unit. Granted, it runs 15's I mean it is stock L03 inside except the cam, but still it pulls hard!
02-13-2002, 11:56 AM
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Car: RS
Engine: LS1
Transmission: T56
Axle/Gears: 9" for the ladies
Your 305 isn't efficient enough to require that much air till a higher RPM. Drop in a 350 with good heads that requires a lot more airflow a lot sooner and you won't pull that high.
I am at that barrier. A lighter car (shane buss) may get down to 13.6's NA. A heavier car a little less.
Basically your limited to high 13's NA on tbi until you go 4bbl
Trust me I am there.
I am at that barrier. A lighter car (shane buss) may get down to 13.6's NA. A heavier car a little less.
Basically your limited to high 13's NA on tbi until you go 4bbl
Trust me I am there.
02-13-2002, 12:32 PM
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So it's not enough for you?
So you are going to do what at this point? How about forcing air into the TBI using ram air or some other cold air induction? Just my .02.
Going with 4bbl might open up a can of worms I would think....
But I guess if you are there... new ECM... New throttle body. New ignition.... New fuel system... Rewire and reprogram everything.... and hold on!
I saw the 1000 and 2000 CFM units.... I just think when you are at that point, it's going to cost you almost the price of getting another beater to play with......
Going with 4bbl might open up a can of worms I would think....
But I guess if you are there... new ECM... New throttle body. New ignition.... New fuel system... Rewire and reprogram everything.... and hold on!
I saw the 1000 and 2000 CFM units.... I just think when you are at that point, it's going to cost you almost the price of getting another beater to play with......
Last edited by Snowdog 91 Formula; 02-13-2002 at 12:38 PM.
02-13-2002, 12:47 PM
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Car: RS
Engine: LS1
Transmission: T56
Axle/Gears: 9" for the ladies
Re: So it's not enough for you?
Originally posted by Snowdog 91 Formula
So you are going to do what at this point? How about forcing air into the TBI using ram air or some other cold air induction?
So you are going to do what at this point? How about forcing air into the TBI using ram air or some other cold air induction?
I was thinking a 4bbl with two injectors instead of four. So far fuel doesn't seem to be a problem.
That or a C@rb. I really don't know.
Everything else is up to par. I've got gobs of torque. but HP just isn't there.
02-13-2002, 02:38 PM
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Aaron, what engine and set up are you running again? cam, heads, etc.? Any moded 350 with 670cfm and plenty of fuel should have mad power, well over 300hp I'd think.
02-13-2002, 06:04 PM
#18
I made over 300 enigne-dyno-hp easily with the OEM SMALL TB unit. the 2" version should be good for 400 with proper injector sizing, tuning and spark management. Of course, good heads, intake, roller cam/lifters and headers/exhaust are also a must...
I'm about 2-3 weeks away from a TBI chassis dyno test with a 7747, ProJection 2" unit with 85pph Holley/dung injectors. No IAC, though. Who cares about that for dyno testing.
I'm about 2-3 weeks away from a TBI chassis dyno test with a 7747, ProJection 2" unit with 85pph Holley/dung injectors. No IAC, though. Who cares about that for dyno testing.
02-13-2002, 06:12 PM
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Car: 91 Red Sled
Axle/Gears: 10bolt Richmond 3.73 Torsen
The stock TB which has super small bores was good enough to get NJSpeeder into the low 14's with heads. From my knowledge the stock 305 can be made to flow enough for a nide 305 or mild 350. The more cubes the more air you want (EFI, not carb specific), so get a larger unit. If the 454 big blocks were using the 2" units I don't see the problem with a 350 using one and making more than 350hp. I believe my engine with the current cam will run a 13.5 at 104mph. I'll go to larger injectors before I go and do the 4 barrel swap. I have plans to control the 4 injectors for high rpm operation but I don't have the money, time, or reason to bother with it as of right now. I think with large injectors and the 2" TB unit you can make over 400hp and I'd love to be the one to prove it .
Holley tech is like calling Summit with questions about a car they have no clue about. If you're lucky you get to talk to an older rep that knows what he's doing. The younger guys are almost always wrong. I never bother calling them for tech support anymore. Most of my questions are so over their head that they just say, "yeah, that might work." over and over and over again.
I wish I had a way to view fuel pressure while going down the 1/4 mile and record it for the board. Again, no money in my pockets for a fuel pressure guage.
If you figured I was running about 300hp when I ran the 102mph you can figure that obviously the holley 670 is flowing enough fuel. I might need to bump the fuel pressure up a bit more but I won't do that until I figure out my fuel pressure.
If you do plan on keeping TBI and doing an engine swap, getting into eprom burning is the best move. You can make your car idle like stock, run like stock, and get stock gas milage.
.Holley tech is like calling Summit with questions about a car they have no clue about. If you're lucky you get to talk to an older rep that knows what he's doing. The younger guys are almost always wrong. I never bother calling them for tech support anymore. Most of my questions are so over their head that they just say, "yeah, that might work." over and over and over again.
I wish I had a way to view fuel pressure while going down the 1/4 mile and record it for the board. Again, no money in my pockets for a fuel pressure guage.
If you figured I was running about 300hp when I ran the 102mph you can figure that obviously the holley 670 is flowing enough fuel. I might need to bump the fuel pressure up a bit more but I won't do that until I figure out my fuel pressure.
If you do plan on keeping TBI and doing an engine swap, getting into eprom burning is the best move. You can make your car idle like stock, run like stock, and get stock gas milage.
02-13-2002, 07:46 PM
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Car: RS
Engine: LS1
Transmission: T56
Axle/Gears: 9" for the ladies
Originally posted by fast_broker
I made over 300 enigne-dyno-hp easily with the OEM SMALL TB unit. the 2" version
I made over 300 enigne-dyno-hp easily with the OEM SMALL TB unit. the 2" version
JP-I can hit 102mph in the 1/4 mile also.
If you use slicks and have the perfect setup, you can probably squeeze 13.5 out of it only due to the massive amount of torque.
I don't see going any lower without a power adder, or lighter then stock car.
I really hope someone can prove me wrong because that makes less swap work for me.
02-14-2002, 12:16 AM
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Jprevost, go to Z28 boy's homepage, he is using a vaccum advanced fuel pressure regulator rigged to work with his set up, which I believe is similar to yours. I bet that would really help you get the pressure dialed in. I saw your car in his pics page, so you may aleady know this, but I thought I'd tell you just in case.
02-15-2002, 09:15 PM
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Car: 1991 Camaro RS
Engine: GMPP 350 HO w/TBI
Transmission: 700R-4
Axle/Gears: 10-bolt w/3.73s
yeah but a a VAFPR is more of a "fix" for a lack of EPROM tuning, which is something that Jon definitely doesnt have 
.
i basically only got mine because i saw all of the info about it so i figured i would try it. there is a good chance that when this spring comes and i start burning chips, i will get back with the stock FPR.
we'll see though. as usual, there are a couple other guys on here that know more about this whole depate than i do...im sure they will throw in their $.02.
-brian
.i basically only got mine because i saw all of the info about it so i figured i would try it. there is a good chance that when this spring comes and i start burning chips, i will get back with the stock FPR.
we'll see though. as usual, there are a couple other guys on here that know more about this whole depate than i do...im sure they will throw in their $.02.
-brian
02-15-2002, 09:25 PM
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900 CFM
I saw a four barrel on the Holley site looking around for an EGR valve....
Thought I would post the picture of it....
http://www.holley.com/HiOctn/ProdLin...IA/f500-8.html
There is the link.....
900 CFM 4 Barrel TBI....
I am not sure if it will work... possibly...
I still think it would be opening a can of worms....
-Snowdog
Thought I would post the picture of it....
http://www.holley.com/HiOctn/ProdLin...IA/f500-8.html
There is the link.....
900 CFM 4 Barrel TBI....
I am not sure if it will work... possibly...
I still think it would be opening a can of worms....
-Snowdog
Last edited by Snowdog 91 Formula; 02-15-2002 at 09:27 PM.
02-16-2002, 01:50 PM
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EGR Valve
Okay, finally done. If anyone gets the Weiand 300-49 intake manifold and needs the EGR Valve.... I'm going to save them a lot of trouble finding the right EGR valve and tell you which one it is after 3 days of hunting for the right one!
It is AC Delco part #1711-3433
It is for an 81 Caprice.
Everyone that needs EGR should know this information. It fits fine and works fine. You will need to extend the vacuum line about 6" so remember to get a little tubing to extend the line.
I hope people find this information valuable.
I know if I knew it, I would have been greatful to have known instead of going through the ol' hit or miss method!
-Snowdog.
PS... we might want this information for people that get the 300-49 or the 300-66 Weiand intake manfold!
Holley, in their infinite wisdom..... They don't have the information. They just say "hook up your old EGR valve", of course.....
Which we all know will not work!
It is AC Delco part #1711-3433
It is for an 81 Caprice.
Everyone that needs EGR should know this information. It fits fine and works fine. You will need to extend the vacuum line about 6" so remember to get a little tubing to extend the line.
I hope people find this information valuable.
I know if I knew it, I would have been greatful to have known instead of going through the ol' hit or miss method!
-Snowdog.
PS... we might want this information for people that get the 300-49 or the 300-66 Weiand intake manfold!
Holley, in their infinite wisdom..... They don't have the information. They just say "hook up your old EGR valve", of course.....
Which we all know will not work!
02-16-2002, 03:18 PM
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First, is the 300-49 for the old style heads? You must be using the aluminum L98 heads. I'm thinking that the 300-66 is the one for centerbolts, and I'm interested in getting it. Did you have any issues with hood clearance. If I run a 454 TBI and the 300-66 on a stock RS hood, will it fit?
02-16-2002, 03:29 PM
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300-49 and 454 TBI
Yeah you can make sure on that. I know the 300-49 fit my engine, but I have a 1985 Chevy 4-bolt main!
Either way, both intake manifolds are the same dimensions and if you plan on using the 454 TBI or the 502-6 I see no clearance issues at all. However.... If you plan on putting an EGR Valve in there you will have to put in a 1" spacer between either TBI.
In which you might have to go with a 2" high rather than a 3" high element.
No EGR: No problem
With EGR: Bolt will have to be cut 1" shorter and 2" high element.
The good thing is... With the spacer on the TBI, you CAN have a flat base open element, rather than the spacer/drop base.
Airflow will be good.
Either way, both intake manifolds are the same dimensions and if you plan on using the 454 TBI or the 502-6 I see no clearance issues at all. However.... If you plan on putting an EGR Valve in there you will have to put in a 1" spacer between either TBI.
In which you might have to go with a 2" high rather than a 3" high element.
No EGR: No problem
With EGR: Bolt will have to be cut 1" shorter and 2" high element.
The good thing is... With the spacer on the TBI, you CAN have a flat base open element, rather than the spacer/drop base.
Airflow will be good.
02-16-2002, 03:35 PM
#27
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well I'm running the stock air cleaner housing, with an L69 snorkle welded onto it, and the taller truck lid with a K&N taller truck filter. It seand to flow great, so I'm not going to run an open element. I guess is could still work, I'd just have to run the stock lid again. Where did you get your spacer, and what's the part number?
02-16-2002, 03:38 PM
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The spacer
Please read my other thread!
I just posted it.
https://www.thirdgen.org/techbb2/sho...threadid=84934
I just posted it.
https://www.thirdgen.org/techbb2/sho...threadid=84934
02-23-2002, 06:26 PM
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Pics of Cruise Bracket / Engine
Here are the pictures of the car as well as the engine compartment. The bottom picture is where I put my fan switch, which I found very convenient. Just run the toggle to ground... the lead goes through the firewall to the fan (green/white) wire. All done! Very simple to do.
The cruise bracket was simple, if you notice, it sits about 1" behind the Holley connector.... It is welded directly to the gold bracket. Very solid, and works great! Remember that because if you have cruise, you will need that from your stock bracket.
The cruise bracket was simple, if you notice, it sits about 1" behind the Holley connector.... It is welded directly to the gold bracket. Very solid, and works great! Remember that because if you have cruise, you will need that from your stock bracket.
Last edited by Snowdog 91 Formula; 03-02-2002 at 09:57 AM.
10-05-2003, 10:50 PM
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Car: '89 Formula, '97 Z28, '88 Formula 350
Engine: 305 TBI(LO3)
Transmission: TH700R4(MD8)
Heres the Holley 670 TBI with 80# injectors for $395. I think its the one that the Holley tech told TBIWorks that Howell EFI sells.
http://www.howell-efi.com/cgi-bin/qu...xact_match=yes
This may be the one that I get for my future buildup. I want to keep the TB but if I can only get 300-325hp max with only 4500rpm's, then I'll go CARB! Does anyone think that this TB would support around 400hp on a 355ci?
The link up top don't work! Go here and click on the acessories, then its on the second page I think.
http://www.howell-efi.com
http://www.howell-efi.com/cgi-bin/qu...xact_match=yes
This may be the one that I get for my future buildup. I want to keep the TB but if I can only get 300-325hp max with only 4500rpm's, then I'll go CARB! Does anyone think that this TB would support around 400hp on a 355ci?
The link up top don't work! Go here and click on the acessories, then its on the second page I think.
http://www.howell-efi.com
Last edited by chevypower; 10-05-2003 at 10:55 PM.
10-06-2003, 12:15 PM
#33
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Car: 1994 Z28
Engine: 5.7 LT1
Transmission: T56
Hey guys I bought a 670cfm Holley TBI but I don't know exactly which one I have. The connector in the back as circled in the picture is not on the TBI I have. Does anyone know what this is?
I emailed Holley but I haven't got a response yet.
Also, what did you guys do about the injector connection and the TPS connections that are different on our camaros. (1992 Camaro)
Thanks,
I emailed Holley but I haven't got a response yet.
Also, what did you guys do about the injector connection and the TPS connections that are different on our camaros. (1992 Camaro)
Thanks,
10-06-2003, 01:17 PM
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Car: '89 Formula, '97 Z28, '88 Formula 350
Engine: 305 TBI(LO3)
Transmission: TH700R4(MD8)
That looks like the idle air controller. You have to cut the wiring clip for the TPS off a truck, besure to get about 7-9in of wire when you cut the clip off. Not sure about the inj connection, been wanting to know if it fits myself! Thanks, Bobby
10-06-2003, 06:05 PM
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WOW, I have not been on this board in ages...I got an e-mail from this post I had subscribed to a year ago and I forgot about this post...LOL I have a 4x4 now and it is sweet; I even joined a Jeep board and you'd actually be surprised to see how many guys on there are former or even current f-body guys. Anyway, I sold both of my 3rd gens and I sure miss them. Maybe someday I will buy another one.
The kid who bough my '92 2 years ago trashed it, it's sad! I work with his dad and his dad is always complaining to me about something else the kid broke on it or wrecked, etc...I sold my GTA to some guy in Michigan last year. Anyway, I just wanted to reply since this was one of my posts to see how things were going for you TBI dudes...Later...
The kid who bough my '92 2 years ago trashed it, it's sad! I work with his dad and his dad is always complaining to me about something else the kid broke on it or wrecked, etc...I sold my GTA to some guy in Michigan last year. Anyway, I just wanted to reply since this was one of my posts to see how things were going for you TBI dudes...Later...
10-14-2003, 06:05 PM
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
***The TRUTH about the CFM on the Holley 670 TB***
I'd like to clear something up.
A Holley 670 CFM TBI is flowed using 1.5"/Hg.
How do I know?
A book titled "Holley Carburetors, Manifolds & Fuel Injection" written by Mike Urich and Bill Fisher.
Chapter 1 Engine Requirements, page 9, last paragraph (which continues onto page 10)....
Chapter 11 Fuel Injection, page 199, first column, sub-chapter The Two Barrel
This should help those of you who are considering upgrading your stock unit with either a Holley 670 cfm unit, or perhaps even a 454 TB with the same bore size.
I was also under the impression that the Holley units were flowed at 3.0 in.Hg based on ‘word of mouth’ on this website.
That’s NOT TRUE. Using the 670 TB would be equivalent airflow to a Street Avenger 670 carb.
Please, moderators, make this a sticky with HUGE bold letters.
A Holley 670 CFM TBI is flowed using 1.5"/Hg.
How do I know?
A book titled "Holley Carburetors, Manifolds & Fuel Injection" written by Mike Urich and Bill Fisher.
Chapter 1 Engine Requirements, page 9, last paragraph (which continues onto page 10)....
Carburetor or injection throttle-body capacity is one way to state equivalent size. It is the quantity of airflow through the unit (at standard temperature and pressure) at a given pressure drop. It is 1.5 in.Hg for four-barrel carburetors and all injection throttle bodies and 3.0 in.Hg for one- and two-barrel carburetors. The higher the flow rating, the bigger the unit. Or, the bigger the unit, the lower the pressure drop across it at any given airflow.
Holley calls this version their Pro-Jection fuel-injection system. Airflow is 670 cfm at a pressure drop of 1.5 in.Hg, equivalent to an 670 cfm four-barrel.
The basic two-barrel throttle-body casting is the same as the larger throttle body discussed in the section on performance replacements. The components assembled to that body are somewhat different.
The 2-in.-diameter throttle bores provide airflow of 670 cfm at a pressure drop of 1.5in.Hg. Even though these are only two barrels, airflow is nearly 12% higher than the Model 1850 four-barrel carburetor and 11% less than the Model 3310 four-barrel carburetor. The point is that this two-barrel throttle-body injector is a very high-capacity piece of equipment, more than adequate for most street applications, especially small blocks. Holley says it is good for up to 320 horsepower. This package is available at considerably lower cost than the four-barrel, so if you don’t need the extra air and fuel flow, don’t buy the four-barrel.
The kits are supplied with an adapter plate to mount the two-barrel throttle body onto a four-barrel manifold.
For some applications a throttle-lever extension, part 20-7 is required. Check with your Holley Dealer or the Holley Performance Catalog.
When this book was printed four kits were available:
502-1 for spread-bore applications.
502-2 for square-flange applications.
Make sure you double-check your application vs. Holley part number before you buy. Refer to the Holley Performance Parts Catalog or Holley Customer Service.
The basic two-barrel throttle-body casting is the same as the larger throttle body discussed in the section on performance replacements. The components assembled to that body are somewhat different.
The 2-in.-diameter throttle bores provide airflow of 670 cfm at a pressure drop of 1.5in.Hg. Even though these are only two barrels, airflow is nearly 12% higher than the Model 1850 four-barrel carburetor and 11% less than the Model 3310 four-barrel carburetor. The point is that this two-barrel throttle-body injector is a very high-capacity piece of equipment, more than adequate for most street applications, especially small blocks. Holley says it is good for up to 320 horsepower. This package is available at considerably lower cost than the four-barrel, so if you don’t need the extra air and fuel flow, don’t buy the four-barrel.
The kits are supplied with an adapter plate to mount the two-barrel throttle body onto a four-barrel manifold.
For some applications a throttle-lever extension, part 20-7 is required. Check with your Holley Dealer or the Holley Performance Catalog.
When this book was printed four kits were available:
502-1 for spread-bore applications.
502-2 for square-flange applications.
Make sure you double-check your application vs. Holley part number before you buy. Refer to the Holley Performance Parts Catalog or Holley Customer Service.
I was also under the impression that the Holley units were flowed at 3.0 in.Hg based on ‘word of mouth’ on this website.
That’s NOT TRUE. Using the 670 TB would be equivalent airflow to a Street Avenger 670 carb.
Please, moderators, make this a sticky with HUGE bold letters.
:rockon: 
:yourock: 
10-15-2003, 03:42 AM
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Car: Turbo Buick
Engine: 3.8 V6
hmm perhaps, but I know of a very reputable fellow to have actually flow benched a 2" bore tbi unit to 670 cfm at 3.0" hg, goes by walt sherwin, was fairly active on diy efi and as i understand it on 454ss.com
I sure hope you are right though
I sure hope you are right though
10-15-2003, 11:07 AM
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Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
Originally posted by Pablo
hmm perhaps, but I know of a very reputable fellow to have actually flow benched a 2" bore tbi unit to 670 cfm at 3.0" hg, goes by walt sherwin, was fairly active on diy efi and as i understand it on 454ss.com
I sure hope you are right though
hmm perhaps, but I know of a very reputable fellow to have actually flow benched a 2" bore tbi unit to 670 cfm at 3.0" hg, goes by walt sherwin, was fairly active on diy efi and as i understand it on 454ss.com
I sure hope you are right though
Not me. :nono: I didn't say any of that stuff. I just copied it.
It's not a matter of me being right or wrong. It's a matter of Holley, Mike Urich and Bill Fisher being right or wrong.
10-17-2003, 03:12 PM
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Car: Turbo Buick
Engine: 3.8 V6
well it looks as though it really does flow 670, kdrolt posted some great info in this post https://www.thirdgen.org/techbb2/sho...&highlight=cfm
11-01-2003, 04:49 PM
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I have two questions on this.
1) Are we sure the guys that wrote the book on the 670 holley are correct on the rating being at 1.5 in HG??
After reading this, I am not sure that has been resovled and after spending the last two years being told that they were flowed at 3.0 , I am very hopeful that this is correct. Any thoughts??
2) Looking at the Holley 670 picture in this post the injector pod set up looks a lot more streamlined than the GM version. I always thought thats were the hang up wason flow so is it possible that the Holly 2" unit flows a Lot more than the GM 2"unit because of better injector pod design??
i wonder how much difference in flow there would be between the holley 670 and the GM 454 with ultimate mods??
Signifigant??
Like pablo, I sure hope the guys that wrote the book are right cause a 350 with a 670 carb and the right combo should go real fast!!!
All thoughts are appreciatted.............bob
1) Are we sure the guys that wrote the book on the 670 holley are correct on the rating being at 1.5 in HG??
After reading this, I am not sure that has been resovled and after spending the last two years being told that they were flowed at 3.0 , I am very hopeful that this is correct. Any thoughts??
2) Looking at the Holley 670 picture in this post the injector pod set up looks a lot more streamlined than the GM version. I always thought thats were the hang up wason flow so is it possible that the Holly 2" unit flows a Lot more than the GM 2"unit because of better injector pod design??
i wonder how much difference in flow there would be between the holley 670 and the GM 454 with ultimate mods??
Signifigant??
Like pablo, I sure hope the guys that wrote the book are right cause a 350 with a 670 carb and the right combo should go real fast!!!
All thoughts are appreciatted.............bob
11-01-2003, 05:11 PM
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Ok, another thought and I quote the book."It is 1.5 in.HG for four -barrel carburetors and ALL injection THROTTLE BODIES". oK, I will buy that with out a doubt if the injector pod is OFF. I hope they mean with it on and are not just comparing the base.!!!I hope this is not semantics.
Maybe there is something to their injector pod design!!
In chapter 11 they say "the 2-in diameter THROTTLE BORES PROVIDE AIRFLOW OF 670 CFM AT 1.5 IN.hG. ""Are they just comparing bore flow to the 4BB? Cause the 4 BBl doesn't have that big injector pod hanging over it.
I talked to a number of people here in denver that flow heads etc and all said that 2-2" bores will easily flow 670 at 1.5. But put the injector pod on and its a different story.
I was seriosly thinking about flowing the unit with and without the pod but don't have the money. Wish we had an R&D dept on this site.
Somebody tell me empatically and with out any doubt that these units flow 670 with the injector pod ON. I will be a happy guy and so will a lot of others.
Thanks again............bob
Maybe there is something to their injector pod design!!
In chapter 11 they say "the 2-in diameter THROTTLE BORES PROVIDE AIRFLOW OF 670 CFM AT 1.5 IN.hG. ""Are they just comparing bore flow to the 4BB? Cause the 4 BBl doesn't have that big injector pod hanging over it.
I talked to a number of people here in denver that flow heads etc and all said that 2-2" bores will easily flow 670 at 1.5. But put the injector pod on and its a different story.
I was seriosly thinking about flowing the unit with and without the pod but don't have the money. Wish we had an R&D dept on this site.
Somebody tell me empatically and with out any doubt that these units flow 670 with the injector pod ON. I will be a happy guy and so will a lot of others.
Thanks again............bob
02-25-2004, 09:04 PM
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Hey folks, I'm new in this neck of the woods. I just started getting involved in my son's 91 305 Firebird in the hopes to steer him back to domestics. From what I've seen so far, I could toss on the "-6" throttle body just by changing connectors. I'm still an old school guy that works by numbers, so has anyone had a chance to compare before and after time slips or dyno pulls with the Holley vs. stock?
Thanks
Thanks
05-13-2004, 02:05 AM
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Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
If any one wants info on the injectors that are probably used in the holley units, they can be found here: injector info
Last edited by dimented24x7; 05-13-2004 at 02:33 AM.
05-17-2004, 02:09 PM
#48
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Car: 88 Camaro SC
Engine: SFI'd 350
Transmission: TKO 500
Axle/Gears: 9-bolt w/ 3.23's
The TPS connector is different. Its the older style 'flat' one. You need to get one of the older style connectors and solder that in place of your present one. This in addition to other stuff youll have to do to use it.
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