I would check dipstick calibration. I cut out a section of the webbing under the rear support so oil can’t fill up in that area, also I plugged the oil feed hole in the end of the park paw. Stopped the small amount oil out my vent.
Chip, if it wasn't doing it before, the new vent location may be just fine.
FWIW, I ran the rear vent relocation also, and had no fluid coming out the vent. I did grind a little extra drainage in two locations on the rib below the new vent. But that rib should not seal to the gasket or the rear support (as cast), but I did add drainage so no fluid could accumulate in that cavity.
In my old race car, I found the 727 could be sensitive to a fluid level too low. Possibly due to fluid aeration if the bottom of the valve body is not covered. So go gently trying to reduce fluid level. If ET/mph drops, the trans could be aerating the fluid. It seemed strange at first, since the deep pan and filter extension will pull fluid from very low, no matter what the level.
