93' Mighty Max 4x4 6g72 Engine Options?

I have a 1993 MM, 4x4, 3.0, manual. I'm having a hell of a time finding an engine for my truck. I have searched for one of these trucks for years! I finally found a good one with low miles and no rust but, the motor has a bad low end knock. Original motors are impossible to find. What is the best route to go? Used? If I can find one! Or rebuild? I was quoted around $3000 for a rebuild. Or is there a simple swap for our trucks? Will a non aspirated 95' (SOHC) Stealth motor fit with minimal work? Please, if anyone can point me in a good direction. I'm not really looking for high performance, just to get it back on the road. Thanks for any suggestions.