Well fellas, tryin to finish up this build and top her off with a carb.

412 SBC (.030 over and a 3.8" stroke crank)
Super Victor Intake
AFR 220s
Solid Roller Cam 264/272 @.050, 649/649 lift, 107 LSA
11.41:1 static compression

If desktop dyno is at the least bit accurate this thing should be making max power at 6500rpm give or take a few, and should not see anything above 7000rpm.

So did the calculation for 100 percent VE for a 412ci motor that sees 7000rpm. Theoretical cfm is at like 830 something. Now seeing how theoretically even tho it should be fine with an 850cfm carb i know that a lot of times stepping it up to another size has actually proven gains. Only problem I am running into is the $ amount from stepping up from an 850-950 is a lot. You guys think this motor will be happy with an 850cfm carb or do you think i should just save up because the gains from going to a 950 carb will be worth it? Thanks fellas :thumbsup:

 

I'll bet that engine will peak higher than you imagine. Also a properly tuned intake and exhaust combo can exceed 100% VE in some cases so don't cut yourself short. I'd do the 950 no question about it.

 

But soooooo expensive lol, what do you think sounds like a real peak?

 

Ha ha! You didn't skimp anywhere else...

That cam is real similar to my Lunati 50144. I'd say you'll get 72-7400 out of it with your heads. The 0-80496-1 is a great carb. Remember that those equations are for airflow and holley rates their carburetors dry. BG says theirs are wet flow.....

 

Wouldnt a wet flow rating be better...?

 

I say yes. If your calculations say you need 830 cfm, and the carb is advertised at 850 cfm dry then you might be better off stepping it up 10-15%. I think power difference will be marginal, but the newer holley HP metering block calibration just seems to be great. I have generally ran larger carburetors than what is "recommended" with excellent results, even after doing many tests with other options. If nitrous was planned then I'd buy or stay with a smaller carb. Big nitrous use lowers the signal, and airflow through the carb drops.

 

Well i do plan on using nitrous in the future (sold my last kit to help build this motor) and I know somebody local who said theyll sell me their 850cfm Barry Grant carb for 370 tomorrow. Think i should jump on it?

 

If its a claw or demon then its worth the money if its in good shape. If its a holley rework I'd hold off until you can afford the 80496

 

Its a barry grant before it got sold to holley and became demon.

 

Demon is all BG. It has never been a part of Holley. It sounds like it may be a reworked Holley by BG, when they did that kind of thing. I would hold off.

 

The BG Claw carbs were too close to a Holley design so BG had to change them into the Demon line. I like a lot of the design ideas in the Demon carbs. I wish Holley did many of them years ago.

Another thing about all those carb formulas. They're calculating a minimum carb size. A race engine will normally always like a larger carb.

Don't complain about the price of race parts. Trying to save a buck or 2 on cheaper parts doesn't always work. Buying a cheaper carb that isn't suited for your engine will just get you frustrated.

I ran a BG 850 Speed Demon on my old 383 stroker. It was on my BBC until I finally converted to alcohol fuel.

 

This is what im lookin at

http://www.norcal1320.com/forum/view...er=asc&start=0

 

Heres the pics

http://img248.echo.cx/my.php?image=carb10px.png

http://img248.echo.cx/my.php?image=carb25xf.png

 

Think its a claw...donno tho anybody , asked dude for a part # guess hes not online right now

 

part number won't help much, unless someone has an old claw book. I don't think I have one anymore. They changed all the numbers when it changed to demon. It is a very early one too. I can't remember seeing one with a choke horn and gold metering blocks. . Its an ok deal I suppose.