[1969_CM2590D]

I don't want to stray too far here, but along with the Pontiac OHC six, the Buick aluminum 215 is interesting as well. Rover took it over and left it largely unmolested in some ways, but cured many weaknesses- many Buick items will still fit. The last version was 4.6 liters (281 CID) and showed up in Land Rover Discoverys until 2005, so it is likely more available than an OHC 6, as well as being proven in an off road 4x4. It's got a GM heritage as well. The dry weight of 318 lbs makes it quite attractive- that's over 100 lbs. less than any of the "lightweight" Chevy sixes! The Rover versions are strengthened, but still weigh just 375 lbs dry.

The Buick/Rover V8 is probably the most hopped up V8 outside of North America, and the most hopped up V8 worldwide outside of those of the Big Three. You can get lots of stuff for it.