If you have the time, pull the 350 and transmission. Take some measurements to make sure the 235 will fit. If you think it will, bolt the tranny up to the 235 and drop it in the hole. You will definitely need to fab motor mounts and probably need a thinner radiator and possibly need to go to an electric fan. There will be all kinds of fabricating and parts chasing. Also, hopefully you will not need to deal with any emissions issues.
Good luck
