Pretty much any of the 700R4 are good transmissions. When I was rebuilding one for an 85 K10, I was told to stay away from the 87 and newer with the auxillary valve body. I guess things change over time.
What you want to look for is one setup for a V8 applications. Stay far far away from the V6 setup.
Make sure you have one with a 10 or 13 vane front pump. Most 85 and later will have the 10 vane pump.
A TV boost valve is something I would definately add. One of their weakness' is not feeding enough fluid to transmission.
http://www.sonnax.com/product-lines/transmission/parts/1799A high outout throttle valve is also a good upgrade. The 700R4 was known for going in and out of overdrive. It'll hold itself until you put your foot into with this kit.
http://www.sonnax.com/system/announcement/77966-94MK.pdf or
http://www.jegs.com/i/B-M/130/70237/10002/-1The last thing would be a shift kit. I like the TransGo kit. It recalibrates things to work more effectively.
http://www.transgo.com/products.php...splay=1&start=0&addcountview=YesAll these parts should give you a good, solid trouble free transmission.