I have an 88 Ram 50 2wd.  This is really a Mitsubuishi.  I have an open diff.  Would love a LS or locker.  I can't find anything.  Can ya help?gp  

The only locker I could find right off was a Detriot locker but it is very expensive. Realistically you would be better off to swap in a a rear axle that has more and cheaper locker options. Since it is a 2wd, this would not be very hard to do either because you do not have to match ratios.  

yeah a rear toyota mini truck axle would be a great swap  

I had one of those trucks for a minute. We called it the "Ja-Par" (Japanese Mopar)...That thing had the stupidest design I've ever seen to this day For front brake calipers! I found out real quick How I got such a nice little truck for $400 that only needed front brakes!