I would think the only advantage would be the '56 trucks had the option of a V8 thus the mounting holes are there and clearance issues are much less. I'm going to beat Cletis to this one - you are not restoring the truck. The proper term, I think, is resto-mod. Whichever way you go it sounds like tons of fun. Good luck.

Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
Support those brave men/women who stand the "Thin Blue Line"! Hug a cop!
USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)