Oh you lucky bastards. That engine was NEVER tied to a manual transmission in the US worth bothering with.
The thing I find odd is, you mentioned converting it to RWD. The engine spent as much of it's life in RWD platforms as FWD, it was designed for 60's buick's, even shares parts with the Rover/Buick 215 V8. The much regarded Buick Grand National was killed because of GM's change from FWD to RWD with that body style.
I'm curious if the cylinder heads on the Aussie engines are any better (or worse) than the US versions.
Later engines did have better heads, also remember we have emmisions laws that are not as bad (for want of a better term!) here. The early heads had some terrible inlet porting, but the later ones they got on track a little.
I do know that early V6's had US sourced heads, and the later ones had much better locally produced ones....I think this was to do with port maching on the exhaust side for the diffrent RWD manifolds used here.
It was 1988 before Australia (Holden) got their hands on the V6 so I guess by that time it had been used in FWD cars for a while.....locations of things like the thermostat housing give the game away.
But I'll tell you from experience, the old 3.8 Litre V6 with a 5 speed gearbox in RWD form (VN Commodore) really is a interesting beast to drive.
While I won't say its as "fun" the Nissan RB30E + 5 speed found in the VL Commodore/Aussie made R31 Skyline (Discounting the RB30ET in the VL Turbo for the moment) due to a much lower rev limit and a horrid sound it does have its attractions such as the mountain of torque just off idle and power oversteer on demand on corner exits! 8) 8)
Also compareing the MF5 (Nissan FS5W71C mid range gear version) gearbox to the Borg Warner T5 the japanese gearbox feels much nicer. Nice and clicky. This is again ignoring the MX7 (Nissan FW5) in the VL Turbo.
Most people here where more interested in screwing power out of Holdens Australian V8, compared to the V6 (Till Holden went to the Gen 3...) so there isn't too much out there, still the local guys have supercharger setups galore and the like. Alot of "hot" bits come from the US.
The manual transmission was the Borg Warner T-5, same as some Aston martins, Ford Falcons etc etc (millions of other things I bet!)