I have a 351M, been rebuilt. I have had it for a year now & has been run great not many problems. But, have noticed lately that oil pressure is & has been good, but really low on the normal side when warmed up. Sometimes it rises or lowers while driving but never below the normal range. Is this ok or do I need to be worried. Should I buy an after market oil gauge so i can monitor it better?

Using 20w-50 oiland have ever since, but I ran 10w-40 in winter time, so that the motor would lubricate quicker (cold). Was that a good idea? or just stick with 20w-50 all year long?

I also wondered if these blocks have low oil pressure after awhile, not very low but low normal? The original 351M that was in my truck before did the same thing, yet ran fine. Anyway, just curious!

Nathan

'79 F-150 Lariat SuperCab.
351M C-6, cam,intake,4bbl,K&N,hedders,
true-dualsw/h-pipe