couple of things
You didnt mention the price you are getting this for, the brand of the AOD, how many miles on it. model of the converter, etc..so it is hard to give specifics here.
stock converter is 1600 rpm stall, is a locking converter, and is meant for a two piece input shaft
buying a used AOD is rolling the dice, unless you can have it tested and inspected you are asking for trouble/ Even if you do. is it setup to run properly in you car? ?reverse/manual valve body? It may be fine or it may have completely wrong shift points and shift super hard.
whoevever told you it doesnt have a cooler because it is non lockup is full of crap. NON LOCK up adds MORE heat than a stock lockup converter. EVERY AOD should have a trans cooler as heat is the #1 killer. especially in performance AOD. GET a plate style cooler- period
4500 stall is WAY too much for your car. You should call the converter company, tell them your engine specs, rear end gears, tire size, and ask them what stall they recommend and how much to reflash the converter or if you need to get a different one for your application. Up to you if you want to keep it non lock up