the 6th gear would be damn near useless lol - not to mention prolly no power at all.. I mean come on at highway speeds im averaging 1300 or so RPMs and that's with a 3 spd with overdrive lolz. - 6 speed what 400 rpms at 65-70 mph? lol that'd be nuts.
But I always though you can mount most trannys up to an engine and it the bellhousing that's the problem, if you customize a bell housing to the engine. It should all work - cept the gear ratios KS pointed out,