Editing My T-5 does not exist

I recently bought an 87 trans am, which turned out to be some what of a flook. The moran's i bought this car from completly screwed it up. Its got an 82 chevy motor in it, overheat's like there's no tomorrow, etc. etc. Anyways, I was trying to find out what year the trani was, but the number of the trani apparently doesn't exist. Sounds like shit to me too, but I can't find anything on it, not even GM can find it. The number is 13-52-066-923. I've visited a number of sites and everything as a quesiton mark next to it. So I dont know. ANY and ALL help would be much appriciated thanks.