"I have a 1950 Fleetline Deluxe with Powerglide. Stock 235--low pressure, babbited, mechanical lifters."

Is that reference to mechanical lifters a mis-type?

If not, did you (or a previous owner) change the lifters to mechanical/solid?
The Powerglide engines in 1950 had hydraulic lifters.

Have you adjusted the lifters? What technique did you use?

Tim
1954Advance-Design.com
1954 3106 Carryall Suburban
1954 3104 5-window pickup w/Hydra-Matic
The 216 and early 235 engines are not "splash oilers" -- this is a splash oiler.