The 465 has a bigger shoulder on the input bearing retainer, which requires a bigger hole in the bellhousing. I doubt if the tri-5 V8 housing will accept the 465 trans, but the 420 you have behind the 235 will handle anything except a beaned-up big block V8, IMHO. You'll need a 3-bolt starter nose cone that bolts to the bellhousing, not the block. I believe any truck crossmember from 1954-up will have the angled mounts. You might want to consider a 400 small block engine- - - -it's got a longer stroke and more torque than a 350, and as long as you run enough radiator and keep it cool, it's very reliable. The exterior dimensions are the same as any other small block engine, and the 265 exhausts should bolt right on, as well.
Jerry
