Oil pressure question.

TT5.9mag said
MS877P (not 9) is a full groove main bearing set for 383 mopar.

edited to add link.
Clevite Engine Parts MS877P Clevite P-Series Main Bearings | Summit Racing

And there you have it. Full grooves with a standard volume oil pump. Genius to sub the P for the 9. I wouldda never thought of it.