zraffz

This is non third gen related as of now (since I don't know if my solid roof camaro will be allowed to participate) but I was thinking about building a street stock dirt track car.

What are the power limits I can expect from a 2 barrel 500 cfm carb so i get a good idea of what I'll need for my motor. As of right now I have a stock 350 short block and a set of stock vortec heads. I am allowed to change valve springs and retainers and am not limited on the size of the cam. I feel like I should leave the heads stock because that carb will choke out the motor with any serious modifications. I'm thinking about leaving it stock and just gearing it very low.

sofakingdom

iTrader: (1)

That carb (Holley 4412) used to be the basis of whole classes of dirt-track cars... I used to occasionally build motors for people in that. Typically it was a "claimer" class; at the time, IIRC the claim on the 4412 was $250. A new one was about $275. So there's wasn't much you could do to the carb.

That's enough carb to make good power up to around 5000-5500 RPM in a 350. You want to run the engine in that RPM range and gear it to keep it there always. If you're not cam- or spring-limited, use a solid cam, tight lobe centers (like 106-108°), low-mid 240s of intake duration. One that it seems like I used sometimes was the Comp 260B-6. Another was the 270TL-6. Look those up, see what the specs are, and look for stuff in that range. Crower has some that are right near there too IIRC. If you can use a roller, look at the good ole 288AR-6.

zraffz

Thanks. I'm very interested in doing this, I figure if we my buddy and I do all the work ourselves (like the welding) this can be built on like a $1,500 budget. I've been pricing everything out and so far I am very far under that budget; I have about $900 to play with now.