Help the New guy. . . Please

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I have been wrestling with my 82 Turbo sport coupe for almost 2 years now. I will now say what it is before I list my Question(s)

Turbo was built in AL extreme mods, no complaints, about a year on it.

3.8 V6 was built about a year ago too by a local shop I trust here in IL. Built to boost, no complaints. not using the computer at all, except for HEI electric advance distributor. . . . .crap that is. . .to be fixed soon.

350 C trans with 2000 stall was built by my trans guy at Oak Lawn transmissions, best I have ever found and aside from needing a neck brace sometimes, no complaints

Problems. . . . . . . .
Well Since I put it together I have had allot of fun, and have beaten some pretty awesome cars, but I am quite certain that my carburetor is too small. I currently have a Holly Street Avenger 670. I have never felt much difference between half and full throttle with it and I lose power and 5000 RPM which I do understand could be due to other factors. I eventually learned that jetting it up to a bit over the Holly 770 stock jets has helped allot, and I find myself wondering why I have limited my air flow to 670. (well actually I know why, it is because it was sort of forced on me by my motor installer) I have also herd from 2 people that used to run carbureted turbo 3.8 motors that the stock Q-Jet was a 800 CFM, but that is was brings me here. Is it true? And Should I now replace my 670 with an 870? A few days ago my bottom 2 bolts on my front bowl have lost the ability to tighten, and I have a substantial pressure leak that makes the car not really drivable, and I don’t want to put the time and money into a carb that is not right for my car. I want to get it put together this week, but don’t know what I should buy. The Q-Jet is long gone to heaven (or hell depending on your opinion) so that is not an option any more.
Thank you to all who have taken the time to read this. Please help.

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P.S. Section 1 is my Unreal Tournament (Video Game) name, I couldn’t think of anything else

 

[blueta]

I believe q jets are 750-800cfm depending on what it was off.

 

[VadersV6]

The quadrajet has, and always will be, a crappy design. The ability to change jetting is very easy and convinient, but the tiny primaries, compared to the sewer drain secondaries make primary to secondary transition horrible. You usually end up with a huge bog when the secondaries open up cause the manifold pressure drops to zero and no fuel can be pulled out of the jets. The accelerator pump doesnt quite make up for it. Now in a turbo application, I dont know how it would react. 670 cfm is probably plenty. You can easily pull over 400hp with it. We used to build alot of engines for top sportsman racing. These were 350 chevys that were limited to a tiny 390cfm 2 barrel. We pulled 430+hp out of all of them.

 

[Section 1]

Thanks for your time Vader!
It was off a 1982 Turbo Sport Coupe and got replaced with the holley 670. It sounds like I need to go up to at least the 770, and I am debating if I should go up to the 870.
Thanks again.

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[VadersV6]

Looks like my point was totally missed.

 

[Section 1]

Looks like my point was totally missed.

Not at all. I have run a few small block 8's before, and I ran a 650 on my best one. I was acually responding to bluetas response, but I noticed you took a bit of time to respond to me which is why I thanked you first.
What I am piecing together at this point is that GM had put a 750 on it stock so I don't see how I was better off going down in size. I do plan to run it over 20 lbs (or more) by next spring if not this fall. I spent allot of money on my Turbo build, and my builder said he was confident that if I get timeing right I can run it at 30 lbs. I am not trying to repair a daily driver, I am trying to make it pretty brutal.

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