If you allready have a useable 292, then use it. There are guys around here using the 250/292 on propane, so the pistons are available somewhere.
There are plenty of books on forced induction. Try
www.motorbooks.com or
www.amazon.com for starters.
A '72 Suburban is probably too wide for your '56. Do you want 5 or 6 lugs? What kind of gear ratio do you want to run?
What does the '56 currently have in it?
Bellhousing, starter, motor mounts, etc... will all be an issue for a 230/250/292 type engine.
What kind of tranny are you planning to use?
