On the passengers' side of the case, will be a machined pad near the rear just above the pan. It has "8" numbers & letters. Start here to ID what you have. If 1992, first number is =2, next three is the model. The rest is identifiers used by GM.
If the front bell-housing on the same side has a large "K", this is truck. It could be rebuilt for 4X2 or 4X4 denpending on tailshaft. If there is a casting in the case the is shaped like an up-side down letter "U" that runs thru the middle of the cooling line fittings, then it was internal TCC lockup. The valve body had no valves but plugs only in late 1987. After that, the valve body removed this section. A valve / spring kit can be purchased for the internal TCC lockup if that part of the valve body is there. You can only see this with the pan off. The "K" indicates a heavier case used in trucks.
Now, the 2nd, 3rd and 4th model, indicates the type & style of wiring strategy used to wire the internals. Temperature, pressure switch and external ECM TCC lockup was controlled thru the electrical connector on the drivers side rear.
My GM Monte Carlo, El Camino factory service manual show 9 different types of wiring diagrams. The detent cable (Called Throttle Valve) cable is important as it controls the internal line pressure as does the PCS / or force motor used on the 4L60e.
Identifying the case and valve body is first to figure out what tactics to use for you application. Choosing to use 12 updated parts will allow you to get 450HP easy, but requires attention to the brand of parts being used and a mild shift kit.
Borg-Warner spray, 3rd shift capsual, Red Alto friction, Kelone plates, wide band, good or new input drum, Beast sun shell, torrington bearing set, Billet over-sized apply piston set, 13 vane pump with hardened rings, 0.500 line boost valve and like mine, ACDelco 5 gear pinion planetaries (Input & reaction) one piece input shaft rings, not scarf-cut type and perhaps re-man torque convertor with a stall speed, that will require research on you behalf to work on you choice of application. I can not pick that for you, but I have done, these, TH200r4, 4L30e and the 4L60e. MD8 is the RPO code for parts, wiring by model which is modified by use and a properly adjusted TV cable. I like the Sonnax TV cable adjustment kit that attaches on the throttle end to keep slack out of the cable when you need it. You can spend $450 extra and get the "Smart Shell" to eliminate end plate flexing, housing clip failures and have room for extra 3-4 plates & steels and bump it up to 550-600 HP range.
It's a choice on how far to go, say if you push snow, you may want to choose they parts, but I just built mine to last years behind my "LS" with extra cooling and used two case wire to add a PTC thermistor for temp gauge readings to keep it below 195F and know what is going on. I choose a three electric cooling fan set up, with low speed, high speed, one dedicated for A/C using a trinary switch, but provided myself with a fan override that allows me to turn on all. The PCM control low/hi, but switch for A/C at R/D, then provide ground via switch but included a diode in each as they control grounds to relays, and eliminate voltage backfeed.
