just a real quick answer please

does a sohc v-tec motor from a 92-99 civic EX fit into a 88-91 Civic or crx without serious modification. if it does what kinda motor mount would i need.

It will bolt in using the stock mounts and tranny.....the 92-95 ex is the d16z6 which is ODB 1 and the 96-00 EX is a d16y8 ODB 2, so the wiring for the y8 will be more complicated than the z6....however both can be done fairly easily if your good with wiring.

no major mods, you may need wiring changes, but if your talking about the d16z then you can use stock tranny, intake(from your si or you have to swap in from the donor car), and you can use your manifold. I believe you can use your stock mounts since its a d series