Re: 'most modern cars will struggle to reach'
Actually, already planned on plumbing a Chevy 350 with a 5 speed trans in there with a carb and ripping out most of the electronics when the 2.9l dies. Nag doesn't have electric windows or navigation, don't use cruise control (vacuum cruise control is available if wanted). Airbag and antilocks (hate the bastards anyway) may be challenging.
I do want to see 500k miles on this engine - this was my first (and last) brand new vehicle purchase. You're not kidding though, I get looks sometimes at the tire place when they find out how long I've had it - I'm the exception evidently, not the rule.