Rare engine. Factory de-stroked 327 (283 crankshaft in a 327 block). I think Chevy only made them for a year and a half to two years, came in Camaros. They would absolutely fly. Always heard them described as the DZ engine.
Your issue is the mounting points on the truck frame. I don't know if 1961 trucks came with V-8s. As Jerry said, either a aftermarket mount, or would have to fabricate mounts. Fabricating is do-able, (we did them on round track cars for years), but a little tricky.
But that is a wicked engine.
Mike
