Sydneykid, thanks for that info, damn i always thought the R33 GTS4 was turbo'd, oh well.
i was going to get the internals re-build anyway so the 33 block may be the way to go (balanced/shot peened crank and rods, forged pistons etc etc)
the only other option i can see is to have a custom sump made up but have it modeled off the original 4WD RB20 one. that way a few baffles could be put in, stop the oil surging at the track
Shane