I chose a Tremec T56 was chosen because it is rated at 440 ft/lbs of torque, and because it was just very cool to have a 6-speed at the time.  (around 2000)  It has been very reliable for me so far.  The first cluth installed was a custom kevlar cluch which only lasted about 8,000 miles, so I put in a Center Force Dual Friction clutch.  The Center Force only lasted about 2000 miles, at which point the organic side disintegrated.  I think that may have been driver error.  :-)   I switched to a Ram 900 clutch, which chattered horribly!  I finally ended up with a Spec Stage 3 clutch, which I am satisfied with.  I'd like to go with a dual disc clutch at some point, but they are pricey!!!

I also installed a Steeda clutch quadrant and a Steeda firewall adjuster with a stock Ford clutch cable.  I love not having to jack up the car and adjust the clutch by removing the clutch cover, it's great!  A Pro5.0 Power Tower shifter shifts the gears, and I really like its short throw and the way it feels.  When Ford finally came out with a leather 6-speed shift knob, I picked one up.  Tremec recommends GM Synchromesh transmission fluid in the T-56, but it is over $20/quart at the GM dealer!  Pennzoil makes it for GM, so it is exactly the same stuff, but is around $6 a bottle.  So, that's what I use.

The rear end is the original  stock 8.8 inch Ford unit, but the bearings were replaced at about 110,000 miles.  At that time I installed a new set of FRPP 3.55:1 gears, a  set of 28-spine Moser axles, an Auburn posi unit and a T/A girdle.  This helps keep pressure on the end caps to reduce the chance of deflection and rear end failure.