Reaming spindle

For a drag car, the SBJ would be superior. Less friction, so easier movement, and probably a pound lighter for the pair.
I really can't imagine anything beyond off road or demo derby, where the BBJ could possibly have a benefit

you are on the money.

the Butch Leal '75 B/MP Hemi Duster I am restoring has small BJs.....big BJs removed....small BJs added when built in 1975 at Butlers shop.