I dunno what the ratios are like to be honest John. I know they are no stronger than the usual gears.

I don't think it's a common box that people fit anymore.

Mine is using a set of S2 ratios shot peened and polished on a new mainshaft (the bit that breaks on an RST box) with larger bearings and a QUaife ATB diff.

The only advantage of changing to a diesel box is if you want to change the ratios as far as I can tell.