90-93 integra rs/ls/gs came with b18a1
94-01 integra ls/gs came with b18b
90-93 integra gsr came with b17
94-01 integra gsr came with b18c1
type r came with b18c5

this should clarify everything.
the b18a block is pretty much the same block as the b18b and u can interchange them.