Going through the archives, I see several owners (@64etype, @Robert_and_Darlene_S, @abowie, @MichaelPMoore, perhaps others) have fitted a 4.2 gearbox to a 3.8 bellhousing/flywheel combo. I need to do the same thing.
Is there a recommended size for the bore-out of the 3.8 bellhousing? (I don’t have a 4.2 bellhousing for comparison.) Or should I simply measure the front bearing dimensions of my gearbox and cut to fit? How snug does the fit need to be?