OK, I'll pipe in once. I would send my heads to Todd at Marsh Performance as he has a great head guy. If you want to spend lots's and have the marque guy do them and squeeze out every CFM, call Tom Hemphill as I think he's done almost as many as Koffel. Fastlane Machine in Utah did a set of B1/MC'sfor me and they are very nice with respectable power in the 1050HP range but I don't really care about dyno numbers. My dragster is 1870#'s with me in the seat and I went 7.55@174 at 7000ft corrected. I would expect 7.20's or better at sea level. Fastlne does great work, and they are reasonable, but expect to wait for 6 months. I'll give you just a brief description of my 572 builds. heads in the 410-420 Int. CFM range, cam in the 840-810 and 288-298@50, 15-1 lightweight pistons, 7.100 aluminum 2.200 rods, well massaged B1 intake, 1150 CFM APD carb. There ya go. Oh...and my B1 originals that I sold Cheatham and related parts, went 8.30's at Las Vegas the year before in the same dragster. i hope this helps.