it has a b21 dohc non vtec i want you to tell me if its a good motor?? and if i can put a b18 vtec head on it????

 

It's a good engine as long as the FRM lining isn't all chewed to ****. If that's the case, your rings are going to go and you will burn oil quite a bit. If you regularly have to add oil to your car, then you arre there already.
Short answer, no you can't put the b18 head on it.
Technically, sure. But you're going to have to 'invest' alot of money into making the passages and whatever the heck else needs to match up.

 

Probably be easier to drop a B18C in there then build a B21 VTEC

 

sh00rik got it, except it's the FRM that chews up rings, not the other way around.

Best bang for your buck would be to swap in a B20A(5) and turbo it, the prelude B20 responds well to boost.

 

ok well whats the frm and how hard is it to replace?? how will i know??? i know it needs a head gasket

 

FRM = Fiber Reinforced Material

It's what the sleaves are made out of.

If the engine has a BHG, it's cheaper to toss the B21 for a B20 (no FRM). B20s are like $300 from a junkyard.