Knew a bloke a few yaers back who had a Corsa 1.5TD in a Westy. Basically an Isuzu engine mated to a gearbox from a some Jap 4x4.
There has been a Westy build featured in PPC with a VAG oil burner.
Guy on LCB has built a middy with a tdi in the back.
Tons of go via the huge torque available.
Steve
