Motor swap question? How much for old motor?

Ok I've still been throwin the idea around for a 5.3 swap. Now I'm gonna keep it a stock daily driver then in a few months Ima get a Camaro as the toy.
I can't remember but can't I get any motor a ling as I get a harness for my yr? Right

also wat do yall think I can get for my motor. It has almost 145k miles(all highway). Regular oil changes with valvoline. New spider injector assembly ($300), plugs, rotor and cap, wires. It only needs a new rear main seal. Doesn't smoke.

I'm assuming 4.3L V6? $500 to the right person. $300 minimum.

yes its a 4.3, thats bout wat i was thinking