stanman

Hey mechanics! I had a 84' 305 Trans Am and it had a Holley 390 on it and it ran sweet. Literally drive all day with out the fuel gauge moving.
I did a swap on my 79' 350 chevy from Q-jet to 390 holley.
I couldn't get it to run but the carb wasn't the issue. Swapped back to the q-jet still didnt run.
Turned out the fuel pump died and it had a hole in the fuel line but I have all that fixed up but I dont have a 390 any more because I sold it and made $70 profit. I want to get another and put it on to save gas, but will a 390 holley work for a chevy 350?

Or should I just convert one fuel tank to Hydrogen geni and use gas and Hydro or gas and propane? Cant really afford to drive any more lol maybe if I hit the lotto and buy a vw bug lol

stanman

Also whats the stock cfm on a 79 chevy 350? And what would you suggest putting in it to lower fuel cost but still be able to tow.

kevinkpk

Dunno, quadrajet, or 2gc? Cfm should be matched to cam lift/duration, and intake valve size, i.e. head. I think in your prior post about a Holley 390 on a 350 sbc, that is a common match with the Holley could be a 600-700 cfm. I've ALWAYS had good luck with a quadrajet over a Holley. Your stock 79 sbc would have come with a qjet or 2gc.
Lower fuel cost equates to keeping your foot out of it, a qjet has smaller primary venturies so, it can actually be less fuel consumption with a quad over a 2 bbl. IMO.

stanman

I did a google search and it says that my stock Q-jet is an 800cfm. I hope its not that big. The junk yard guy said to put a vacuum gauge on there and adjust it to use less vacuum. This left me confused as all hell; he also mention 2brrl but I really dont want to put a 2brrl on it. I'd still like to do the occasional run and towing.

kevinkpk

I used to have quad numbers link for what went on what. If it is an 800 cfm it won't be a 2 barrel for sure. The quad number is going to be a 17xxxx or older a 7xxxxx. If it is a 800 cfm it would have probably been on a Cadillac or some large car. You can "really" never over carb an engine, but you can certainly undercarb one. CFM is actual fuel/air mixture through the venturi(s), this dosen't mean you will be stuffing that down the cylinder if the valves cannot handle it, just means it has that capacity.