A while back, there was some forum discussion about a thin wall deep socket that will fit down into the spark plug wells on a pre-war Buick engine.
I use ACDelco plugs and just bought a thin wall 7/8 spark plug socket from "SNAP-ON" (part no. SFS281 USA). It's pricey at $30), but works fine on my 1931 8-57.
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1931 Buick, 8-57 4 Door Touring Sedan
1936 Plymouth P2, Deluxe 4 Door Touring Sedan