I'm haveing a big debate with my friend, and decided to settle it once and for all. So:
Can you use roller lifters with a non roller cam?
Thanks for replys

NO!.......

I guess bob is probably right, I've never thought of it before. What would be the point of spending the money on the roller lifters anyway? The cam isn't ground to take advantage of them even if you could use them. Despite the errors in popular belief, roller cams don't make more power because of friction losses.

K

NO! Is the short answer.

No because flat tappet cams are ground with a very small amount of taper to make the lifter rotate, lifter is also specially ground with a small crown for same reason.
Roller cams are ground with zero taper and rollers are perfectly round with no crown no taper.
Roller cams use a retainer plate to keep them from moving forwards, flat tappet cams have the tapers ground so the cam is being pushed back against the block.
Put roller lifters on a non roller cam and it wont last very long. Thats the somewhat long answer.

No, the lobes of a flat tappet camshaft are different, they are narrow compared to a roller cam. The side of the roller lifter contacts before the roller does if tried with a flat tappet camshaft.

lol, thank you. That shut him up damn quick.