I"m running the 08-501-8 in '98K2500 5.7L with 24x igntion, 0411, roller rockers, upgraded comp 26918 springs, and BBK TB. The 08-500-8 was not in stock when I purchased, so went a hair bigger with the 501 which was in stock at the time. Can tell you I'm still working with BB on dialing in the...