Done this once or twice. Yes on the v8 motor mounts. Chevy V8 will bolt up to chevy auto trans, OD units as well. Hell, even bell housings for manual trans. Lol. You will need exhaust manifolds, exhaust. I am unsure what headers will fit a van, but I've seen them installed. More radiator, aux trans coolers for towing. Should be some v8 build threads on here too.
Welcome! And good wrenching!
"Who New? Blue"
1990 Chevy G30 454
Church Van, maternity division
1988 Dodge B250
'94 Dodge B350 www.xplorermotorhome.com/
Xplorer MH model 230 230 hp MPI 360 LA Wedgy OD auto
Old vans never really die if we chose to let them live