senjorb0b

I have this 350 engine and the guy that sold it to me, doesnt know what year it is, he guesses late 70's early 80's but it doesnt have any pollution stuff. he said he put a cam in it, but doesnt know what...and he has a 750 cfm double pumper on it..
is that too big of a carb for that motor?

thanks alot
Andrew

Damon

For a double pumper? Maybe. If it's got a dual-plane intake then, no, it will work fine. If it's got a single plane intake it might get a bit boggy down low unless you use it with a higher stall converter to keep from getting into the "soggy" part of the power band.

senjorb0b

i know it has a single plane manifold, we replaced the 750 that was on it with a new one, and it still doesnt run right, which made me think it was the size of the carb. the 4 barrels dont like to kick in on their own, and when u drive it , it bogs down and wants to die..
i guess its just too big of a carb
and since i have ran it, even though its only been like 2 weeks, i cant return it to summit..so now im stuck with it. unless someone wants to buy it.

well thanks again.
Andrew

JRoy91RS

Have you tried jetting it down? Try 78-80s for the primaries and 88-90's in the secondaries to start. Then work your way up from there. Also, with the Holleys you can play around a little with the fuel pressure. You should be able to get the 750 to work.

Jester

No it's not too big. Might have some tuning issues, or even some mechanical issues given the attention to detail the last guy seems to have had, but there is nothing wrong with a 750DP on that.

Stroked-Z

IMO...if you got a 750DP in good shape, you have stock heads & a mild cam.....its too big for that motor.

What type of engine setup is it? What heads & are they stock? What cam & its specs? What intake & its specs? What trany/stall/gear you running? WHat is the main purpose of the car?

Answer all that & we can recommend whether the carb is too big or not....and if it is, we can tell you what you should be looking at.

Another thing, make SURE it is a 750. Dont guess on it or all of the above is invalid.

senjorb0b

well il tell ya what i know about the motor. its not in a thirdgen but i could really use the help
its in a 1970 monte carlo that im redoing, i just bought it
he says he put the motor in but doesnt know what year it is but he thinks its like late 70's early 80's. It doesnt have any emissions components. It doesnt have any serial numbers or id codes on the front of the engine, id have to pull it to check the back of it.
the guy says he put in an aftermarket cam, but doesnt know what the specs are , it has a holley single plane high rise manifold, and a brand new holley 750 cfm double pumper.
Im about to just pull it and take it somewhere and let them figure it out.

JRoy91RS

If I were you, I would get a book on how to tune Holleys. Get yourself a vacuum gauge to determine how much vacuum that cam is pulling. You should be able to determine what size jets and power valve you need based on vacuum.