Looking at the picture of the plug after about 50 miles of street driving would you think its under carbed or just needs bigger jets? The bottom of the threads is even whiter than the picture shows.. Motor is a BBC 496, 10.5-1, eagle rotating assembly, modified Pro Comp heads with larger valves and matching cam springs, cam is a solid mechanical with .260 @ 050 and .677 lift.. Timing is locked out at 37 degrees as it was on the dyno... The motor made 667hp/650tq on the dyno and is topped with a un-modified Proform 850dp.. When i received the motor all 4 idle screws were only 1/4 turn out..