it's indisputable that not having the original engine is going to hurt the resale price and is going to ding you in any concours judging.
on the plus side, Buicks don't tend to have the grossly inflated prices of Ferd / Chevy / Dodge, so it's not going to absolutely kill the resale ... because it's not bubbled up anyways.
The way to crush the bourgeoisie is to grind them between the millstones of taxation and inflation.
Government schooling is about "the perfect organization of the hive."
H.H. Goddard, Human Efficiency (1920)