The 454,s I have built for a truck with a lopey cam where 2-wheel drive trucks, which I drove on the open road a lot where they where running at higher RPM's. These engines definitely where not real responsive on the bottom end when leaving a stop light. These cam's where in the mid 290 (advertised) degree duration, with about .490 lift. I had the head spring area machined opened up for larger single spring (with inner damper spring), in order to run more lift without having to go to dual springs, which are rough on cams for street use. I had this one 1977 C30 with a built 454 go 85-MPH for 2-hours straight on the open road without breaking a sweat.




