When I bought my 1990 it was a mess. Blown topend, seized bottom end, bad seals in the suspension, and of course a stripped drain plug.
Since I was cracking the case I went ahead and tapped the whole to a larger size and installed a Sure Drain from FRAM, for a Chevy 350. If you haven't seen the sure drain it is is drain plug which actually stays in the drain plug hole. It has a cap which is removed and another cap with a hose on it to drain the motor. It as rather slow draining but there is little chance of stripping the drain plug as you do not remove it.
I had my case apart so I made sure that the plug was flush with the inside bottom of the case. Also it sticks down from the bottom of the case about and inch so I made a skid plate to protect it. It did not actually protrude from the bottom of the frame rails but I wanted to make sure that if I ever cased it hard I would not rip it off.
Woody223