I hope since some of you here own/work in a shop,maybe someone could give me a rough estimate on how much it would cost to have th engine and trans taken out of one car and put into another of the same car,engine swap is the word im lookin for.the car is an 80s 300ZX or Z31

$500-1000 is a typical cost. Remember though, you get what you pay for. If you see a slightly shady shop wanting to do it for a few hundred dollars, don't expect the swap to be very good. Imagine how much you care for your car before committing to a lower deal that you might regret later.