Best bet for a 91' Prelude Engine Swap??

I just bought a 91' prelude Si and need suggestions for engine swaps, what say ye?

do you have the b21a1? (2.1L) well i don't actully know what motors can fit in them, i got a 91 prelude si as well with a 2.1L, i was told i can put a acura 6 cyliner in it, with little to no modification. i also was told by a specialist that a performance motor, H22A Vtec will bolt into it. goodluck and if you find other info. let me know.

the best engine to put in would be a h22a they bold right in all you will probably have to do is do some modifications to the wiring harness get rid of the b21a1 if thats what you have they are junk i have the b20a5 in mine which is the better si motor