Ok this one may be a bit of a tuffy. When I bought my 82 Z-28 it came with a rebuilt "350" in it. Well at one time it was definitly a 350 but now I have no clue. It also had an 800CFM Holley DP on it and it ran like crap. The timing was way off and both power valves were blown out. I replaced the power valves, and hit it with a timing light and got her running properly, a little rich but not too bad honestly. She ran fast and hard with the 800. I have since dropped the 800 (thinking it was a mistake doing so) and put on a 750 VS Holley, now both carbs had to have a spacer under them or it wouldnt run right. I also tried a 650 and it wouldnt run at all with or without the plate. Now that I have the 750 VS on it and have adjusted the timing accordingly it does run good but no where near as good as it did with the 800. So I'm wondering what should I do? The intake on it is an Edelbrock Performer. And I'm using an MSD Streetfire Dist and Box. So any suggestions? I'm thinking a 770 Street Avenger II and maybe an Edelbrock Victor Jr intake or a Holley Intake. So let me hear em.

 

A 650 should be more then enough for most 350's.To start whats you motor combo specs ? And if this car if mainy street driven the victor jr is out of the equation. Stick with a dual plane for the street.

 

im no carb guy, but if it ran great with the 800 on it, y dont you put it back on?

 

I don't really go for that whole carb/cid calculator crap, to many variables, my 350 did not want to run with a 650 it would nose over at 5000rpm...I am currently running a 800cfm Holley myself and it runs like a raped ape up to 6500rpm.

That being said getting back on topic, like already stated if it ran good with the 800 why try to fix what is not broke?

 

I cant put the 800 back on because it had a cracked body(ignorant friends). I dont know the motor specs as I bought the car with whatever this combo is. And just like 4playta mine will nose over a 5K with even the 750 if I dont have the velocity plate in it. A friend of mine thinks the heads on it have huge intake runners. Which makes me think part of the problem is the shorty headers and cobble job y pipe that is more like a T pipe. So now has anyone ever used the 770 Street Dominator II?

 

There's no way either of you need a 800cfm carb on a 350 smallblock unless its an all out 600hp race motor. And this has nothing to due with a carb calculator either. And now having a 750 vs on a 4 speed car isnt the greatest idea either. Like I said before a 650 dp would be a good start and a 750 dp would be the biggest i would go with a 350 streeted small block. Tuning is the key to having the car run, not putting the biggest cfm carb you can get your hands on. Figure out your cam,head specs and then pick out a carb.

 

I tried the 650 idea and had a veteran carb guy tune the thing and all it did was cook my headers to the point they were glowing red hot. All he had to say was the 650 was too small. I have no idea about anything internal on the motor, hell it could be a 383 for all I know, the farthest I've gone internally was adjust the valve lash. And as I said before she runs with the 750 VS and the timing retarded waaaaaaay back, but it's at a sacrifice of about 1500 rpm. I really didnt want this thread to turn into a pissing match of that carbs too big or no it's too small. All I wanted was some idea's thrown out there like try this carb or this intake/Carb combo.

 

Sounds like "veteran" carb guy isnt that good. If you headers were glowing red you were running way to lean or your timing is way off would be the 2 biggest contributors. I would aleast get the casting numbers off your heads and try to figure out what you have and firgure out you "full race cam". And as said before learn to tune your carb. No one can give you direct answer on what to use if you dont know what you have. Then you will really have some mis matched stuff and the car will really run like crap.

 

Well I am looking into a head and cam package from Dart but that will be a little ways down the road. And also when I had the 800 on it she had a nice lopey idle, and now with the 750 it's gone. So I dunno. And how do I figure out what cam is in it. I'm trying to get all the info I need as I am currently in the last week of my third tour in Iraq

 

Ok I did get some info. I got in touch with the gentleman I bought the car from. The engine is, a 72 High Perf Pass Car Block, Bored .40 over with JE Forged Flat Top Pistons, Eagle H Beam Rods, A Scat Forged Crank, Clevite Bearings, Molly Rings, Cam is a Lunati .490" Gross Lift with a 230 duration. Heads are Single Hump Cast Irons with 2.02 Intakes 1.60 Exhaust Stainless and a 3 angle valve job, valve springs are dual bee hive style. I cant remember what he said about the keepers and guides but I doubt thats important. He said the Edelbrock Performer is on there because he ran a Qjet during break in and swapped it for a 750 DP after he started having issues with the Qjet. He is not sure why his kid took the 750 DP off and put the 800 on. Now what is the big difference between Vacuum Secondaries, and a Double Pumper (other than the obvious that the DP has 2 power valves and 2 acc pumps)

 

I have kind of the same engine, granted mine is a 383. Performer intake and same distributor. I have the e-tec pro heads, im using a street avenger 770 and it works perfect.

 

Thats a decent motor but the heads arent the greatest. A double pumper is for performance and racing with autos with high stalls or stick shift and the VS is just for cruising and for automatics. Like I said before that VS thats on there now is not good for a 4 speed. With your current combo you can run a 650 or 750 dp at the most i wouldnt go any bigger. And you should get s0mething like a performer rpm/air gap intake or a weiand stealth/ air strike intake setup for a 4150.

 

K so the 750 VS is just not the right carb then? And what is a 4150? A Holley obviously, and if I go with a Holley I will more than likely swap out the Edelbrock Performer for a Weiand Stealth or one of the Street Dominator Intakes.

 

A 4150 is the double pumper style. It can be holley,demon,ect. I wouldnt go street dominator either. Looks like they wont flow well after 5200 rpm. The weiand and edelbrock are good to about 6500rpm i believe.

 

K I'm getting a 4150 750 CFM HP series Double Pumper, it has no choke but I never use one anyway. Now how about a Weiand Team G intake or X-cellerator?

 

I wouldnt run a single plane intake on the street. Dual plan intake is more then enough. You better get a jet kit for the carb also. Your gonna possibly be jetting down some with that carb, and might as well pick up an air bleed kit also.

 

Whats an Air Bleed kit? And the Stealth/Air Strike intakes are the only dual planes Weiand makes? And what about a Holley Contender? Is it a dual plane?

 

Air bleeds let less or more air into the mix. There like jets but for air. There screwed on to the top of the main body.
http://www.summitracing.com/parts/HLY-36-240/

And yes i would stick with one of those 2 intakes you had metioned.Or go with the edlebrock rpm or air gap.

 

So the Holley Contender would be a good choice?

 

I run a 4150 650dp carb with the choke horn milled off on a Weiand team G single plane intake and it works great on the street with my setup. The only problem is it is very cold blooded so if it was my daily driver I would do something different. The only thing I might change in the near future would be to get a 750dp HP main body kit for the carb. I know some people would never use a single plane on the street but if you have a low enough gear and high enough stall converter the single plane is a great choice. I wouldn't use a VS on my lawn mower, I did a back to back seat of the pants test with a 750vs and the 650dp I have now and the 650 dp would rape that 750vs. My 2 cents.


Mark.

 

WTF is that ?

 

The Holley Contender is based off of the original Z/28 intake. And the Weiand Stealth is based off of the Contender

 

Never heard of it and i dont see it on there site so I dont know.

 

Holley Street Dominator it's called now.

Edelbrock Performer RPM is a good choice. Or Weiand Stealth.

 

You dont see it on their site because it is called the Stealth by Weiand now, I did a little research and found all this out so I bought it as well as a 4150 Chokeless HP series 750 DP

 

Holley still carries both their name brand, and the Weiand models (bought out Weiand a few years ago).

 

See that's where the variables Come into play because my motor Dynoed 564 at the crank with 12.1 forged pistons, AFR 210 heads and Isky 580-A solid lifter cam -- .580"/.585" 262/266 @ 0.050", 106 LSA. It will not run right with a smaller carb, I am even thinking about a bigger carb like a dominator and see if I can squeeze some more out of this motor.

Carb calculators work alright when working with a stock motor but when you start modding it throw all those calculations right out the window, it now becomes trial and error, what might be the perfect size for one 350 may be way too small or big for another.

 

4play our motors are similar your comp ratio is a tad higher (I think I'm at 10.5:1ish) and your cam is bigger (haha thats what she said) but the builder did say she ran brutally hard with a 750dp and the 800 was a bit much

 

Yep only thing I can tell you is experiment with different carbs until you find one that makes you happy. I am pretty happy where I am at right now but I feel there is a little more to be had...just dont know if I can justify the price of a Dominator to find out so I will probably stick with what I have. If your cam is a little smaller and you have a little less compression I would think a 750 DP would work good for you.

 

I still said nothing about a carb calculator. And if you read my post you would see i said a 800 cfm carb dosent belong on any street motor which your motor isnt. Your car is all top end and if you do drive it on the street it wouldnt start really moving until 2500-3000 rpm and wouldnt be any good under that.

 

well I really appreciate the help and suggestions guys, I have a new intake on the way as well as a new carb. Now I cant wait to get back to the states and check it all out