detailed info here:
http://m42club.com/forums/showthread.php?t=538&page=3cliff's notes version:
M42, blueprinted, balanced, bored, stroked, and squared to 88mm with a M47 diesel crank, custom rods, wiseco pistons. M44 valves, M50 lifters, Beehive valve springs, a ton of custom work to the head and intake manifold.
Engine was also made into a 'non-interference' setup, for good luck.
Lightened steel flywheel + a ton of other stuff.
No dyno yet, estimate 200 hp at the crank on a stock chip w/7600 rev limit; g-teched 1/4 mile at 14.5 seconds at 97 mph (est).