Other than a ZC, and a 88-91 si are there any other engines that will directly
bolt into an 91 DX. Will any of the newer d series motors fit?

 

yes
any D series engine will bol tinto ur chassis except the A1 off the 87 teg... need mounts... but using stock mounts u can use the 88-00 D series..

 

Yeah... in the case of the Z6/Y8 you need to use your car's stock driver's side engine mount bracket an machine it so that it doesn't hit the timing belt.

 

dont b16a engines bolt directly onto 92-00 civic chassis as well? i heard that was true, but you need engine mounts to bolt in a b series into a crx. so...my question is, if a b series bolts straight into d series mounting, but the crx will not accept a b series without new engine mounts(or fabricated), how does a d series from the civics(z6, y8) bolt into a crx? confusing? sorry. dont no how else to put it