Originally Posted by plumcrazy
70mm TB's will cost you power on a Paxton car. I had Greg good heads, DLM built the motor, 14lbs and was at like 870rwhp no meth. The best thing you can do when building a Paxton car is talk to Doug Levin. He will always talk to you and help out.
I have spoken to Doug Levin, Chuck Tator and Kevin at Exotic Engine Development. I was told that 70mm TB's will hurt low speed driveability without the supporting mods such as (forced induction, heads, cam headers tune etc. With a bigger cam the 67-70mm TB's proved to be worthwhile. Also, you have Greg Good heads to get 870rwhp. Did you upgrade your CAM? I am currently pushing 720rwhp without heads or a CAM and hope to improve my numbers to the 900rwhp range with the Striker heads/cam and a 2.75 pulley upgrades.