Over-carbed?

[Knanthrup]

Lately I\'ve been debating with myself what CFM rating of carb to get. I pretty much decided on a Holley, and have seen a lot of 650\'s but I was thinking 650 may not be quite performance oriented enough to feed my engine. I see a lot of 600\'s and 650\'s on stock or lightly modded 350\'s but I ended up biting the bullet and bought a Holley double pumper 4160 750CFM today. I\'m hoping this will be the right match for my engine and everything.



I know that you guys will need to know my specs to make the determination so here they are:

350 crate block

#450 heads, enlarged valves (2.02/1.60) and machined, bowl hogged, guide boss ground

Comp Xtreme Energy 274H cam, .490/.490 lift and 230/236 duration @.050

Oh and an Edelbrock performer dual plane intake.



The guy at the machine shop that did my heads said with a similar setup they made almost 400HP and on the comp website they have a dyno sheet of 370hp on a slightly lower tuned version of my engine so I\'d guesstimate that the carb will have to feed inbetween 370-400hp.



Anything else I missed? thanks...

[ZZ4Blazer]

My motor was designed by the techs at GM. It is the 4th gen HO 350. They\'ve spend many hours and dollars testing and tuning.



They recommend a 750 Holley for my motor, and Im just pushing 355 hp. Not for long though. http://www.s10v8.com/images/smilies/icon_wink.gif



I think thats a good carb for that motor. Especially since you have a stick shift too. You\'ll probably have to jet and tune it though.

[td_iwhs]

I have been kind of wondering the same thing about my set up. I have a performer intake and a 650 Edelbrock carb. I took it off my friends 350. I was wondering if it would be a little too large? It was free though so i was\'nt going to complain. Any thoughts??

[350-s-10]

i think it all depends on your CI of the motor and the cam and compression that you are running..... i know that winston cup motors run something like 27:1 compression and make over 750 hp out of something like a 450cfm carb with a restrictor plate..... so it all depends, the only reason that they run so much compression is to try and suck down as much air as they can..... me, i have a 750 edelbrock on mine, thats what is recommended by edelbrock with their RPM package and it makes over 400 hp! and if ya think about it, the CFM rating is how much air can flow through it, so you can always change the jetting..... the only thing is if you go too big, then the air will not be sucked down with a big enough force and the fuel will not be atomized into the chamber..... hope this helps, i would recommend no bigger than a 750 on a 350, but a 383 might take a 800, but thats gettin big!

[DWG]

The Holly web sight gives you the information you need to pick the correct carb size for your engine. You will not only have to play with jetting but you could find the squarters are not right. You can bog the engine down by either to little or to much fuel. The accelatior pump cams can also be changed. It will determin when the spray comes in and how much you will get. I found it very difficult to get everything adjusted just right.



For your size engine you want to get the 30cc squarters not the bigger 50 cc ones.