johnny, the 218/230 is probably the most common. the 265 truck engine is very strong and if you're very lucky, you might find one with factory dual intake and dual-outlet exhausts! semi tractors, dump trucks could be bought with 265s in 'em, but i can't remember the years....like '49-'51.
i rode in a '29 desoto a while back with a '50- something 265 truck engine and the performance was amazing. i believe chrysler and desoto had a 251 cubic inch engines. the 218/230 sixes are the same length. the 251/265s are about 2" longer. if you could squeeze the straight-eight into your car, you'd really have a smooth machine, but i don't know about the differences in your ability to build power into them. check with don coatney...he's really into these engines and he's a storehouse of info, too.
