Thread: Carb Advice Needed!

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Ok got a SBC 383 stroker.....comp cam intake 283/281 Exhaust, .603/.600 in. Intake Lift, .590/.587 in Exhaust. AFR aluminum 1110 heads. 220/65CC intake Runner Volume (cc): 220cc, Exhaust Runner Volume (cc): 80cc. Super victor intake manifold. Street driven. I have a 700R4, 3,000 stall, 411 posi.
I dont want to be like all those other cats and over carb. I have too many conflicting opinions.

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Well, this looks to be a balls-out street race motor where bigger is better. A healthy 355 will need a 750 to make max power and it stands to reason that a healthy 383 would need an 800 to make max power. You have enough cam and more than enough heads to make power to 6300. I've put a lot of motors on the software dyno over the years and I can see this motor making 115% efficiency pretty easily, so using the formula CFM = Cubic Inches x RPM x Volumetric Efficiency ÷ 3456, I can see 802 CFM working out well. With a 3,000 rpm stall converter, I would use a full-mechanical double pumper, leaving the manufacturer of said item to be determined by you.

You did not provide the piston info, so I can't figure your static compression ratio, so I don't know if the motor will be friendly with pump gas or not. If you have not completed the assembly of the motor yet, cut the block decks to arrive at a squish/quench of between 0.035" and 0.045" to help prevent detonation on pump gas, using a 0.039" to 0.041" composition head gasket to prevent fretting of the aluminum cylinder heads. Ideally, the cam will want 9.75:1 to 10.0:1 static compression ratio.

Note for the other members of ClubHotRod who have not used a 4-pattern cam yet.......
Screwby has used a CompCams 4-Pattern cam in his motor. This is the first of its kind that I have seen in the forums that I frequent, so it takes a little explaining.

When you're using a single-plane intake manifold such as a Super Victor, you can divide the motor into two different cylinder groups. There are 4 cylinders that are closest to the carburetor (3, 4, 5, 6 on a Gen I SBC, called the inboard cylinders), and 4 cylinders that are further away from the carburetor (1, 2, 7, 8 on a Gen I SBC, called the outboard cylinders). It stands to reason if you think about it, that the outboard cylinders fuel and air requirements would be different than the inboard cylinders fuel and air requirements.

For years, cam grinders have used a 4-pattern cam on NASCAR motors and now the technology is showing up for street motors as well. That's the basis for this young fellow's motor, a 4-pattern cam using 1.8:1 rocker arms. Here are the specs on his cam and some remarks by Comp and Summit......

08-604-44 - 4-PATTERN O.E. Hydraulic Roller Camshafts

https://www.summitracing.com/parts/cca-08-604-44

In addition, here's a tutorial from CompCams......
https://www.youtube.com/watch?v=3aL_G2GM3zM

Me personally, I would not be using an overdrive trans in this combination. OD transmissions are for fuel mileage and require a much milder cam than what the OP is using here. This cam, at its sweet spot, will be revving higher than what an OD trans needs to run at to make fuel mileage. I would have used a well-built TH400.

I would also not have used a Super Victor or the cam that the OP chose because the dual-plane, high-rise intake that I would have chosen would not need a 4-pattern cam. The OP is counting on max power at max rpm's, but on the street, that's not how it works. You need to be making max power from 3000 (or wherever your converter stalls) to 6500 and that is where a dual-plane, high-rise intake manifold shines. The OP will be down on power from mid-range to top end by using the Super Victor. This has been proven many times on the dyno. If the OP were using a 6000 stall converter and a cam that would pull to 7500/8000, then I would agree with using a Super Victor.

Building a fast car is about building a fast COMBINATION of parts that rely on each other.
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