727 fluid level?

I have a 72 dart 360Magnum with a custom built 727 trans that I bought at the end of 2005. The torque convertor is a baby 8 2800 stall. How do I determine that the trans has the proper fluid level. The trans has a deep aluminum trans pan, An adjustable aftermarket dip stick that I believe is adjusted improperly. I drained the trans and approximately 6 Qts. Came out, so I put in 6 Qts. But the dip stick reads overfill both cold and warm.

Any help would be appreciated.