Welcome to the next installment of the

Topic of the Week

to run from 4/12/02 to 4/19/02

The subject for the week is all about intake manifolds for the TBI.

some suggested topics:

- smog requirements
- Vortec intakes
- TBI to carb intake adapters
- part numbers
- prices
-

 

summit part number: HLY-300-64 Intake Manifold SBC Weiand "Stealth" $159.95



summit part number: HLY-300-36 Chevrolet: 262-400, 1987-up 305/350, aluminum heads, Street Dominator intake manifold ... $116.95



summit part number: HLY-300-38 Chevrolet: 262-400, 1987-up 305/350, aluminum heads, Street Dominator intake manifold ... $107.95



summit part number: WND-7525 Intake Manifold, Aluminum, Team G Street Ram, Chevy 262-400 W/EGR $183.95


summit part number: WND-8000 Chevrolet: 262-400 EGR compatible, idle to 6,000 rpm, aluminum, Action Plus, intake manifold ... $139.95


summit part number: WND-8004 Chevrolet: 262-400, idle to 6,000 rpm, aluminum, spread bore, Action Plus, intake manifold ... $97.95


summit part number: WND-8016 Chevrolet: 262-400, idle to 6,800 rpm, aluminum, Stealth, intake manifold ... $108.95


summit part number: WND-7546 Chevrolet: 265-400, 1,500 to 6,500 rpm, standard square flange, aluminum, X-CELerator intake manifold ... $109.95

 

summit part number: WND-7547 Chevrolet: 265-400, 2,000 to 6,500 rpm, standard square flange, aluminum, X-CELerator, intake manifold ... $91.95


summit part number: HLY-300-49 Chevrolet: 1957-86, 1987-later with aluminum heads 262-400, Pro-Jection intake manifold ... $171.95


summit part number: HLY-300-66 Chevrolet: 1987-2000 350, with cast iron heads, Pro-Jection intake manifold ... $193.95


Edelbrock:
Summit part number: EDL-2701 Chevrolet: 262-400, for use with 1986 and earlier cylinder heads, dual plane, non-EGR, cast aluminum, Performe... $129.95


summit part number: EDL-3704 Chevrolet: 1987-1995 305/350 throttle body injection engines, EGR, idle to 5,500 rpm, aluminum, Performer inta... $210.95


summit part number: EDL-7516 Chevrolet: 262-400 engines with 1996 and later Vortec cylinder heads, 1,500 to 6,500 rpm, aluminum, Air-Gap in... $219.95


summit part number: EDL-7116 Chevrolet: 262-400, with 1996 and later Vortec (L31) cast iron heads, dual plane, 1,500 to 6,500 rpm, aluminum... $173.95


summit part number: EDL-7104 Chevrolet: 262-400, dual plane, square flange, non-EGR, 1,500 to 6,500 rpm, aluminum, Q-jet Performer RPM inta... $149.95


summit part number: EDL-7101 Chevrolet: 262-400, dual plane, square flange, non-EGR, 1,500 to 6,500 rpm, aluminum, Performer RPM intake man... $124.95


summit part number: EDL-2975 Chevrolet: 262-400, 3,500 to 8,000 rpm, aluminum, Victor Jr. intake manifold ... $169.95

 

What about the victor jr intake?
On a decent 350 with vortec heads and the Lt4 hot cam it was worth an extra 10hp from 412 to 422.
Also let's not forget how TBI doesn't have the same problems with fuel distribution at idle/low rpm operation so a single plane with decent designed runners can make you more power EVERYwhere in the powerband.
The only reason I didn't go with the victor jr. on my car was because I didn't have the hood clearance (stock hood) and I wasn't sure if I was going to keep TBI or go with a carb.

 

I'll put it up later. I've been putting those up for over an hour. I'm pooped

 

Well since so many people on this board will be running
the World heads you'll see that they recommend the Dart II Sportsman intake #061010

 

Ive had several different dual planes and single planes on my TBI setup.

I definitely like the single plane better.. more topend, and you dont seem to lose bottom end because of the fuel injection.


I have had a Torquer, Torquer 2, and a weiand stealth..


honestly, i couldnt tell a diff between the different single planes, but i could tell a difference between a single and dual.

Dont go spend a ton on the best single plane....

My favorite intake on the car was the blower intake.

 

i know this has been asked a million times but since its the topic of the week.. what do we have to do if we buy an intake without egr?? will the car run right or will it sputter.. do we need to have a custom chip burned and can we pass emmisions without the egr? lots of cheap carb intakes without egr... thanks

 

need adapter plate p/n and a pic if possible.

 

 

So you guys are saying to definatlly go with the single plane? I was going to get the Edelbrock Vortec Performer that's a dual plane, mate that with L31 heads and an LT1 cam, but I wanted to see some decent power from 4k to 6k, single would be better then?

 

I'm planning on running a ZZ4 intake on my 305. It already has provision for EGR, and I see them for sale pretty cheap. It really worked well on the street on the ZZ4 in my Chevelle, allowing it to pull hard all the way to 6K. I was using a Holley 650DP on it, and it should be more than enough for the 305. The Performer RPM on the velle now has better mid and top end, but would be wasted on the 305, even with cam, Heads and exhaust. I can't say about single Vs. dual plane, but I'd guess torque down low would suffer slightly with a single, while giving upper end power.

 

This is the exact reason why we made intakes the topic of the week! TBI doesn't have the problems with fuel distribution at low rpm!!!! This alows us to use single plane intakes and now loose so much low end like similar carbs.
So if you've got the hood clearance...get a single plane, you could probably extend the "rated rpm level" down another 1000rpm just because of TBI. So if the intake is rated at say 3500-8500, it's more like 2500-8500. Infact at lower RPMs TBI has a better fuel atomization compared to a carb...it's up high when things start to get a little iffy.
Then again it's still questionable considering you could slap on a 500cfm carb on a single plane wild 355 and have an awesome idle/low end torque, just depends on how flexible a design and how much money you've got .

 

So what would be a good single plane vortec manifold? And do you have to have a cowl, it wont fit under a stocker?

 

The only one I know of its the edelbrock super victor.
GM might have their own version too. Shane B had a Edelbrock torker intake on his 355 TBI but I think his heads were drilled for the old intake pattern and then had the intake and or the head port matched.

 

Tas, don't you mean the victor jr.? The super victor is a large single plane and I don't know anybody with less than 600hp that's running with one let alone under the stock hood.
Just go to edelbrocks website and check out the intake measurements and understand that an RPM (air-gap also) fit under the stock hood with a little work.

 

The guy was asking about Vvortec single planes. The Victor Jr. doesn't have a 4 barrel Vortec version that I can see. There is a 2 barrel Vortec Victor Jr. and there is 4 barrel Super Victor Vortec which is what UnderDogRS bought.

 

Since we're on the topic of intakes this week, this will be the perfect time to ask this question. I'll be doing an intake swap in about 2 weeks and was curious as to which intake everyone recommends for my car. Mods are minimal but are in the sig. Hood clearance is not a problem. I was thinking along the lines of the Edelbrock Performer RPM and all i would need is just the carb adapter right? Any opinions would be more than welcome since i wanna order the part hopefully by late next week...

 

There are lots other choking points before the intake. Maybe do those first, headers, catback, gears, posi. Get a cam and do it the same time as the intake. But that's just me.

 

Well heres the thing...my car has got bot 145k miles on it now...its really starting to run good now... i still have an oil leak (which has slowed considerably since winter) which is coming from the intake...i know i could probaby just fix the seal or whatever but i mean as long as i'm there, may as well? Headers i wanted to do...but i gotta keep this engine up and running for as long as possible...gears i AM doing shortly along w/ posi...catback...eh, my exhaust is MORE than enough for me...so i dont know...what would you suggest in my situation Tas?

 

get a used edelbrock TBI intake.
I got a weiand 7547 since it was $95. I have NO top end HP on my car and I thought I'd see what happens with it.

 

So what would be the best (and by best I mean the best results without needing a new PROM) combination intake/cam for a 305 with 1.6 lifters, 3.73 gears/posi, headers and 3 inch exaust.

It seems like there are so many but I guess each application is different huh. Price is not an issue as long as it all works.

Part numbers would be great as well.

 

stupid question, but for the single plane intakes, the manufacturer says they can only be run on either aluminum heads or 86 and earlier cast iron heads but not the 87+ cast iron heads. does anyone make single plane intakes that fit the later 87 and up intake face on the cast iron heads or am i missing something?

 

This is kind of an intake topic. The Edelbrock MPFI conversion for TBI. I would like to know your guys' opinions on this.

 

Mine is Holley all the way!
Love it!

I love the choice I made.

 

Tas and Jprevost, I know you guys have had good luck with your carb intakes. I took a different approach and bored the TBI intake out to 2" to match my 454 TBI. We have done numerous chip iterations and I now believe we got the fuel and spark dialed in but I cannot get consistent performance above 5,000 rpm. Some times(very seldom) with smooth throttle it will pull strong to 6,500 and it is awesome and other times (most of the time) it just hits the wall at 5,000 rpm. Do you think it could be my tbi intake? I am really tempted to swap it out for a carb model ie something good to 6,000 or 6,500 rpm to see if that is where the problem is.
I am sceptical about the carb manifolds given the adapter plate
seems like it would be restrictive. But the proof is in
the results you guys have gotten. Do you think my problem is the manifold??
Also, my "tuner" who has a pretty good reputation in denver(yeah, so what) has told me that the carb manifold does not have the water jacket underneath and as a result gives inconsistent performance. He built a dual tbi manifold and had an aluminum jacket welded to the bottom of the manifold. It is still prototype but they got some awesome runs out of it in an open roadster. I know the tbi manifold did have the water jacket underneath and it is consistent up to 5,000 but not after.
Have you guys run into inconsistent performance with these manifolds?

Finally, I need to run egr.Which carb manifold would you recommend for a stoc
This is a lot of stuff, and I really appreciate the
help.....................bob

 

rsilver, how is your fuel pump? Is it an upgraded aftermarket model or the original? If it's the OEM pump, it could likely be holding you back above 5000rpm...you might want to check your fuel pressure during a WOT run at 5000+ rpm and make sure it doesn't drop off at all. If you have, and it doesn't, I really don't know what it could be...an intake is just airflow physics and physics don't have on or off days so I can't see it being the intake manifold.

 

just elongate the four center bolt holes

 

I do think the stock bored out TBI is too small for any mild 350. It's got the smallest plenum volume I've ever seen on any intake. However, I don't think this is the problem. Like it was sugested, I think you've gotta fuel delivery problem. Not only are the 65 injectors small but the stock fuel pump will not flow as much with increased fuel pressure (to get the injectors to support the hp).
I'm in the same boat. I'm running with a stock fuel pump and the 65# injectors on a 330hp motor!
I'm going to get a new fuel pump as soon as I can afford it (this summer). Definatly check the fuel pressure under WOT.

 

I installed a walbro high flow pump and had absolutly no improvement above 5,000. I don't think the pump is the problem. I agree, if it was the manifold it would never run to 6,500 but it does sometimes and most of the time it doesn't. This one has had me stumped for about 9 months now, and it could still be a chip problem. I am gonna double check ignition, but its all relatively new so I don't think thats it. I am running the stock coil.
Do you think a better coil would help with the problem? Thanks............bob

 

I never really thought about it, could the size of the stock fuel line be a problem with building power? I ran 1/2 inch aluminum on my Chevelle, but I don't think I wanna mess with the Camaro's fuel lines.

 

I have the Holley 300-36 intake manifold. They advertise it as an 87 and up, but I had to modify the bolt holes in the middle, as they were the wrong angle. Works just fine, great intake manifold. I had to modify a few things, like there was no provision for the brake booster, so I had to put a t-fitting in the one vacuum hole provided, and my friend made throttle extensions, as the lines could not reach the throttle body. It took a little bit of fabrication, but it works just fine, a lot better than the stock intake.

 

rsilver, have you tried any bigger injectors with that 454 TBI? You have done what I have been thinking about but I was thinking larger injectors. I wasn't sure the duty cycle would go low enough for a 350. Any experience?

 

Paul D. and J prevost. I checked into the injector issue early on when I was planning this project and based on what I read and
what the "tuner " told me the cop 65# injectors seemed adequate. When the tuner worked on the car he said the 65# supplied pleanty of fuel. In fact we pushed up the fuel several times on the chip at WOT and it ran worse at high rpm. I talked to troy at howells EFI and he also felt that the 65# were adaquate
and suggested running the FP all the way up and all the way down to see which direction we should take the fuel curve. It actually runs better with the FP all the way down on the afpr!!
As a result of that I had the "tuner" take out 5% fuel at wot
and it seemed to help the breaking up above 5,000 rpm but
the power is still not there,(we have several chip iterations with even less fule, but no help) and there are still those days that it pulls hard to 6,500 and puts a big smile on my face. My BL numbers are fine at all RPM as indicated by my scan tool .

I know I have gone beyond the TOTW and I appreciate all the comments. I don't think its the manifold either (not saying the carb one wouldn't work better but it probably won't solve this problem). Anyway, if ya got some ideas and want this subject off this thread
please e-mail me.
Once again thanks--------you all ROCK!!!

 

Hmmmm, Paul D, I re-read your post about the 85# injectors and the duty cycle of the 65# being LOW enough for the 350. I guess I don't understand the concept of duty cycle enough to know what you are getting at. I thougt it was simply a matter of
larger injectors supplying more fuel and if the 65# supply enough
fuel, then 85# won't help. Maybe I have this screwed up. I will check the archives on the duty cycle issue and get a better understanding but if you all got any ideas on why 85# may help, I am all ears. Thanks again.............bob

 

TTT

I wanted to bring this one back because I have seen many intake manifold swap topics recently where I felt the suggestions (as far as CFM and single vs. duel plane) were a little off base. Maybe this will provide a better forum or at least answer some newbie questions.

Speaking of questions...

Would it be possible to run an EGR manifold on non-egr heads to give the appearance of having egr (for visual inspection), but non of the side effects? Would there be any issues with this? Just an idea, that's all.

Later all,
Harry

 

sure, just install the egr components on the inake and then disable teh egr in the prom so the ecm wont flag the error. Im not 100% sure but i think the ecm also adds in 5 degrees of timing when the egr is activated. I heard that somewhere so i think if that is so the extra time nulls some of the effects of egr activation at partial throttle. The egr is closed under WOT so there is no effect there.

 

elongate the holes in the intake

 

and the intake of choice for a stock 91 TBI 350 in a Blazer with 4.10 gears would be?

 

some would say one thing others would say another. its up to you, assuming your want low end torque right off idle i would check into dual planes - like a weiand stealth

 

oldie but a goodie

 

woa... long time, no post, tas.

 

Sounds like I ought to get a single plane. I'll be putting a performer on my soon to happen rebuild, but that's mainly because I've got one already. If I get a single plane later, that will make for an interesting comparison.
The Holley 7525 seems like a good one 'cause it's a spreadbore (which fits the TBI bores a little better) and it's got the EGR pad.
Also, it isn't that much taller than stock. All of which has me thinking that with a black paint job and all the legal goodies in place, with luck, it might pass the visual inspection.
Anyone got any input on that?
Tailpipe test?
Also has anyone who's tried a single plane noticed any sacrifice in lugging ability?
If you can help, Thanks

 

I dig it when an old post comes back. I never did try that ZZ4 intake. I ended up selling it and going with TPI. Now I just need to EBAY my tbi stuff.

 

Here's another question that has not been really addressed...

When using an intake that has an air gap between the runners and the base (like p/n EDL-7516) what kinds of problems arise aisde from the usual hood clearance issues? I'm sure that there must be difficulties with cold start/idle since it will take the manifold longer to warm up and thus fuel distribution and vaporization will be affected for much longer during warm up on cold days than with a regular intake.


***Yet another topic that needs to be looked at when purchasing an intake that gets overlooked quite often... (not a question here so much as just something to consider before buying)***

Bosses for CTS, nitrous systems, etc...

Which intakes have 'em? Which ones are already tapped and which ones are you gonna have to invest in a tap and dye set for?

 

Sorry, I've got to resurrect the topic for another question.

I just picked up a performer manifold and want to run my TBI on it. My buddy is going to machine out an adaptor for me. I've noticed though that the Performer manifold doesn't have the fitting in the front (immediatly below the tbi on the drivers side, facing the front of the car) that the TBI manifold has. The line looks like a fuel line coming from the manifold (perhaps a return line or line to evaporation canistor?) EGR will be disabled on this car, if that matters. What should I do about this? Just tap it into the manifold?

Thanks,
Mike

 

What is everyone's thoughts on using a manifold with no exhaust crossover?

 

Burnt blues, the steel line comming out of the stock tbi manifold is a brake vacum line. They don't want it to lose vacum, thats why it is tapped into the manifold. you can run a vacum line off the back of the manifold I am told or go ahead and drill and tap a hole for your existing line. Hope this helps..................bob

 

I might have missed it but, how much does a tbi adapter usually cost?

After I read this post the creative juices started flowing and I got an idea. A 1 1/2 plane intake! Take a dual plane and grind down the middle ridge halfway and sharpen it to a point. In theory it would produce more torque than a single plane and more hp than a dual plane. I don't know just an idea.

Also would a tbi adapter act as a tb spacer?

 

thats been done. You need to be careful of how large a hole you cut into the divider otherwise, alot of the effect is lost due to the resonance of the air column in the slot being out of the range that the engine is normally in.I have some formulas to help calculate how large of an area to cut out. ill see if i can dig them up.