XJ607

I have a 1997 jeep cherokee 2 door.. and it has had the motor swap.. its pretty hacked up in there.. theres random wires and plugs not hooked up to anything and its pretty ghetto.. kinda pissed me off but i got the jeep for 400 bucks so i can't complain...
BUT MY QUESTION IS:
How can i tell what kind of motor is in there.. i'm thinking its another xj motor but with all the haggard connections and **** it makes me feel like it a new xj motor or another jeep. .does anyone know how to tell how what motor it is?

ALSO: what motors would fit in there nicley? and what motor would be the best to put in there with out crazy modifications: some mods are okay but i don't want a **** ton and don't want to spend a **** ton of money ..

any answers would be greatly appreciated THANKS!!!