When Buick came replaced their aluminum V8 and V6 (selling that 215 cu in V8 to British Leyland was one of the dumbest moves on GM’s part) with the 300 cu in V8, the V6 was basically the same, the obvious difference was the 2 rear cylinders lopped off. Both engines shared piston and valve assemblies, but the V6 crankshaft needed to be balanced differently because of vibration issues specific to a V6 design.
The numbers don't match on the 300 in it... doesn't have the aluminum heads of a '64, and it's got a dinky little 2bbl Rochester.
I am wondering if I should gonapeshit and find a 455 to dump in it and rebadge the thing as a early GS fantasy rig or some such... Riiiiight!
Quarterpanels first... good luck with that.