Sounds like a win.
The distributor may be the same as 340, 350 so HEI may drop in?
IIRC those engines had a cast alloy accessory cover that tended to eat its pump parts, but I assume that if it's already assembled that know to be good. Be careful about high oil viscosity.
I would be using log manifolds just save save work and reduce underhood temperature.
Carburetor is 4GC? If it works I'd just use it.
IDK if the oil pan from the 215 Olds or later SBB fits to give you choices of sump placement for crossmember, center link, etc.
Picked out out a transmission? Do you need a super low 1st for crawling? Does it have a bellhousing?
