It is a common swap, but is a fair amount of work, too. The old Chevys are narrow, weren't designed to take a V8, so things are tight. It can be done, though. Motor mount systems are different, so plan on drilling, cutting, maybe welding, etc.
The 350 will tear out that old torque tube rear end, so you are right to change everything. But that's more work and money.
Have you considered either hopping up the 235 or putting in a 250 or 292 six?
Cheers!
George
