Carb sizes

[Voguely]

Hi all,

I've currently got a '77 Corvette C3 which is supercharged (crate 5.7L GM engine underneath). I've been having dramas with it (due to timing it seems, but I won't go into here as it's already in the corvette forum) and thinking of putting it back to N/A as I suspect the issues are S/C based/caused.

At the moment it's got a Holley 750 carb on it. If I go back to N/A will it be ok to keep such a large carb on there or should I drop back to a 600? If I do it, I'll probably use something like an Edelbrock RPM intake manifold in place of the charger.

Any thoughts welcome, particuarly in relation to carb size. Thanks!

Edited by Voguely on Saturday 3rd November 22:40

[chevy-stu]

is it not worth trying and get the supercharger set properly ?

this might help.... though it seems to recommend on the conservative side..
http://www.holleycarbs.com.au/chooseCarb.htm

[Fleckers]

Keep 750 and rejet if needed

But I would get it on a rolling road and setup with the s/c correctly

Edited by Fleckers on Monday 5th November 07:30

[Voguely]

I know taking the S/C off seems like I'm giving up, but I'm just not convinced that there is the level of expertise over here to properly tune these things. This car has already gone through one engine and I'm not up for buying another. The SC was fitted by an 'american car specialist', as was the new crate motor.

Im not overly bothered about having something with insane power, I just want to be able to walk up to the car, start it up and be able to drive it without it breaking every time. If that means going back to N/A then I'm happy to do that. Plus I reckon I could do it more or less cost neutral if I can sell the S/C afterwards (new ones are about £1500 once you include shipping).

[jeff8407]

IMHO, a 750 CFM Holley is a little to big for a NA Chevy 350. Yes, it will work, but you'd need to have it set up by someone that knows how to tune them--I think you'd need to send it off--that runs about $300-400 here in the states. Even then, unless you want big HP #'s(450-550hp), it is not necessary. I think your best bet is a Quickfuel 630 Vacuum Secondary, or GM Quadrajet(great economy and throttle response and can be tuned for power--check Ebay in the U.S. for updated performance models).

On this side of the pond, virtually no one runs superchargers on a daily driver when for about $2500 you can build a Chevy 350,383, or 400 that is capable of making well over 500hp on pump gas.

I hope this helps--ditch the supercharger and get a good set of heads and a smaller carb. You will be happier.