Well today I finally got ALL the parts needed for my new-ish 750 Holley (which added up to nearly the amount paid for the carb itself).
I had previously a Rochester Q-Jet from a 78 Vette.. the engine is still basically the 78' 350 Vette just rebuilt. I got a new carb for several reasons, such as random idle speeds, gas leaks on the manifold not due to the gaskets, odd shifting. The car finally started with the new 750 carb on it after several attempts of the car not even turning over. My question now is what exactly does the white smoke coming from the carb mean in conjuction with the air/fuel mixture being lean or rich? I've turned the screw in all the way and back out 2 turns and 3.. it hasn't really much started or kept running.. when it does run it sounds really choppy (which is cool in a way) but it sounds nothing like it did with the other carb on it along with white smoke coming out the tailpipes with a real heavy smell of gas.
The fuel levels in the bowls are fine as well. Would changing carbs also cause the car to sound or idle much different than any other?

 

I've gradually turned the fuel/air mixture screw a fourth.. and gradually it gets closer to starting but when I shut off the key gas fumes and squirts out from the carb.... any explanations?

 

Have you checked the float levels?

Have you changed the timing since it actually ran?

 

No, haven't changed the timing, even though that's a problem with the old carburetor as well. Not sure what the set up of all that would really be for my engine and everything. Were going to put a new power valve in the new carb and see if it'll work. If it doesn't start then my next question would be where to go next lol It's hard to tune it all if it won't even start... I put the old carb back on today and it started up just fine.

 

you may need to remove the fuel bowls to make sure the float is set close. if this has center hung floats turn the bowl upside down and set the float to about 1/2" between the float and bowl on both floats. you could have a bad power valve also. make sure it does have one on the primary side. only the camshaft will make a normal choppy idle.

 

also if you take the bowls off check the numbers on the jets and power valve. if the engine has a mild/stock cam you should start with a 65 power valve. main jets should be between 71-74. read this thread too https://www.thirdgen.org/forums/carb...ng-sticky.html

 

Alright thanks! I'll see what can be done! Not a fan of our parts shop, they have to order everything and it takes forever.