I have a 431. Not a ton of racing times with it...last summer I was able to get a best 7.88 8th, 1.78 60ft, at 89mph. Put on a set of indy ez on, has a .570 Ultradyne 251@.050/278. There is alot of tuning to do yet. I run 4 speed and 4.10 dana. I have done nothing but find the weakest link since I put the ez's on it.