Our search function doesn't work very well usually, but if you just look at the thread titles and check the ones that look like they may cover it you'll find TONS of threads on this. You can also check this thread for some good info on hybrids,
http://board.marlincrawler.com/index.php/topic,5628.0.htmlWith only a stock 20r head on a stock 22r bottom you won't gain too much. Warm up the head a little though and it'll give good gains. It's really a matter of how much you wanna dump into it.
I can personally tell you that going from stock 22r to slapping on a stock 20r head made my engine more usable and stronger everywhere. I'm currently replacing a headgasket and will be dropping in a slightly bigger cam, but will be building another hybrid with big valves and port work in the near future.
