Can I take a motor out of a 1993 Chevy Silverado pickup and put it in a 1999 Chevy Silverado pickup

It would probably be a wiring nightmare and it may not pass inspection if some of the smog equipment wasn't there , that's aside from if they sniff your tailpipe , It's usually best to go with how they were designed .

Never work. Totally different computer system. Totally different fuel injection. (TBI or open manifold fuel injection in the 93 direct cylinder fuel injection in the 99) Different intake manifold. Totally different wiring harness. (no transmission wiring in the 93, 12 wire connector in the 94, 13 wire connector in the 99) Completely different transmission (TR700 in the 93 L60E in the 99) and transmission control method (mechanical in the 93 electronic in the 99). It would be easier and cheaper to simply restore the 93 or find another 93 body to drop the engine in.