Dear Mike;
Multi-grade oil doesn't work well in the 'older' engines, SAE 30 is much better, for that reason. Some add a pint of STP also.
This works great in mild climates, but may have limitations in Pa. (wintertime) etc.
Copper is best, make sure the line & ALL fittings are clear, first.
If there's no improvement, switch to SAE 30 (4 Qt) & see the difference. If there is, add a pint of STP & the readings will then,, come up to 'normal'.
A 50+ reading is 'normal' when cold for a used engine.
You'll need a 5+ minute "warm-up" in the lower temps.
Happy trails.
