I have a deep 727 pan on mine. Works fine. Chrome with cooling ribs. Got it off the auction site for $20 or so. Thought it was a "leaker" but new design dipstick and seal fixed my passenger front corner leak (at least for the last 3 days). Good luck, I know it is frustrating

 

I hate to tell you this, but that Mag-Hytec pan is the nicest one on the market-PERIOD!! I have installed other aluminum ones, and a bunch of the deep steel ones. There is just no comparison-NONE. Keep in mind that you get what you pay for!!

 

Just finished with the same problem. The problem I found out is steel bolts being threaded into aluminum tranny housing too tightly. My tranny was due for fluid change after being rebuilt. Found out tranny shop had inserted heli coils into most but not all of the bolt holes. Bought a heli coil kit (then made my own bolt to use instead of the insert tool supplied), then replaced all bad heli coils and drilled, tapped, and inserted new ones in the holes that didn't have any. Can't say I was happy about doing it but it worked for me.

 

Are the bolt holes in your pan flat or bent from tight bolts, even slitely. Check that the pan gasket surface is flat , or put the edge of the pan on the edge of your work bench and use a small ball peen hammer as a punch and hit it with another to bend the pan holes back flat.