Quote:
Originally Posted by Chad-1stGen
I don't get this? How does changing the base but not changing the cam specs gain 60 hp? Was he saying that just having the large roller bearing surface frees up that much HP? Any engine experts able to explain this?
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For the same reason not all cams with advertised duration of say 290 deg are the same. The ramps are very different and hence the actual timing events. That's why a starting point for cam comparisons is to use the measurements of duration at .050 of lift.
Mopars used to have an advantage in the flat tappet cam world because of their larger base circle cams.
Roller lifters allow for more extreme timing events and a larger base circle allows you to have even more aggressive ramps without the lifter binding. Optimizing the opening events is what cam timing is all about and the larger base circle gives you the ability to do so. Cam lobes get closer to square. Open to full lift quicker and close from full lift quicker.