727 trans help!!!!!

You might just have an "all manual" valve body. When you get the car drivable, if it is not now, do some experimenting.

If it will start out in 3rd (not actually drive, but actually STAYS in high/ 3rd gear)

If it will start out in 2nd and STAY there

Then you have a manual valve body

These come in both "standard" and "reverse" pattern, IE PRN are in the usual place, but with a "reversed" body, it goes PRN123, as mine in my 67 does

But a "standard" pattern would have 3rd in place of drive, so PRN321, as opposed to factory, PRND21