HQ Belmont Ute, 308, M21, Air all factory

[Big Rob]

I am pretty sure it was to do with fan driven compressor, engine speed etc. Engineering manuals explain it but it has been years since I saw them. A WB with 4.2 auto and GV4 is a 3.36 rear axle.

Thanks, that explains why it's not revving it's guts out on the highway. I thought the diff must have been changed, although the old bloke I bought it from said everything was original.