Hell for $100 or so you can buy bolt-in mounts to let you put a 250 where a 216 was, the mounts on the 230/250 are the same as the small block V8 -
I see is as a toss-up, the choice being primarily whether one wants a pre-60s look or not. If buying the complete overhaul kit, the one for 235 runs something around a hundred bucks more....
The 235 has been in for a quite some time now. It runs great. I've got a few 235's laying in wait. Never going to use anything but the old stovebolts. I'm chopping the top and about to have Rusty build my ch***is. I'll start a builf thread soon.