Cylinder Head question

This is going to be a tad bit confusing so I will start from the beginning, I bought a 91 LS it had a b18a1, long story short the guy said it was no crank, no start, well got it home and starting looking at it and he threw a rod through the block, the cylinder head had bent valves, so I took it apart and 2 of 4 valve guides were broken instead of me getting valve guides for it I would like to know what year b20 head will fit my b18a1 block, what modifications will I need to do and will my exhaust header and port and polished intake will fit on the b20 head. TYIA

Any year b20 head will bolt straight on, and your intake and exhaust will bolt straight to that too.