If you have lifter wear, there will also be corresponding damage to the cam lobe it's riding on. I don't think there's a suitable roller lifter that will interchange, and there would have to be a fair amount of modification to the block to keep a roller lifter running in line with the cam lobe. Flat lifters are designed to spin in the block- - -rollers have to stay aligned with the lobes.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!