750cc carb on a 304

i got a 750cc carb you think it would be to much for this motor it pretty much stock but a 4bbl intake and hei ign?????????

 

Way too much. 500-600cfm range is about right.

 

What about a holly 670cfm street avenger

 

There's always a tradeoff between fuel control and size in carburetors. The larger a carb you use, the more fuel you can pack into the cylinder at wide open throttle (WOT). However, as the carb gets bigger, the available engine vacuum decreases. Carburetors use vacuum to control fuel, and the less vacuum you have, the less control you have over the fuel/air mixture.

You can make a big carburetor work on a comparatively small engine bu making the fuel mixture rich all the time. Clearly, this will affect fuel economy.

So, I expect if you want to use the SA 670, you can make it work. The Holley street carbs are lousy performers on a Jeep though.

Instead you could go to one of the Truck Avenger carbs, which are set up to work well off the pavement, and have annular boosters that provide better mixture control than the street carburetors. Holley would recommend the TA470 carb for your application.

http://www.holley.com/data/types/pictures/TA_IntoZOOM.jpg

 

thanks for all the info i tell ya yall guys are a great source of info and def save me alot of money over my jeep build i just wanted to say thanks for everything

 

x2 on what Tim said.

I'm putting a TA670 carb on a fairly healthy 401........

 

What Tim said. And as an extension, the vacuum problem becomes even more acute at higher elevations, to the point where if you managed to tune it for say sea level, it probably would not even run at 10k feet and would run like crap at 5K elevation. Unless you are into retuning the carb on the trail, best to stay on the small side. A 750 will feed a reasonably healthy 454 and was even too big for my 381. For a 304, something around 450-500 cfm will probably work best.