[Chris Hill]

Originally Posted by dwight southerland

bill -

if you are working on the turbo slant 6 project, it might be that the effort ($$ & time) spent trying to put a roller cam and lifters into the motor would not have enough roi to be worth it. I do not believe that there is enough power to be gained above 6000 rpm or so to warrant the roller setup. The slant 6 valve train is light enough to be controlled with available valve springs at that engine speed. Remember that a flat tappet arrangement has the design characteristic to have much faster off the ramp acceleration and faster ramp action under .150" lifter rise than a roller cam and that is a great benefit to the performance of a boosted engine. I would spend more energy on camshaft profile for a flat tappet cam than get anal about a roller lifter moving the valves. I bet there wouldn't be a 2% difference in power output after five years of thrashing between a flat tappet engine and a roller tappet engine. Imho

the cylinder head flow is your biggest limitation on that combination.

x'2

Very well stated too!