too thick...
Why are you using a straight SAE 50W oil??..unless you have really loose bearings, or no rings left, and its smoking bad,there is no reason to use SAE 50W oil in any chevy motor!..its way too thick for this time of year,your motor,if it starts in this cold,will suffer until oil flows to all the surfaces it needs to lubricate..its best to have oil pump up quickly,and cold 50w is like maple syrup,and can take quite a while to reach the places it needs to be quickly!..
Heavy viscosity oil will always increase oil pressure...if your running a high pressure pump that will increase it two fold,and I've actually seen main bearings FAIL from too much oil pressure--it can carve a groove in the bearing babbit,then the pressure bleeds off and dumps into the crankcase,instead of flowing to all the other bearings..its rare,but does happen..
If your motor doesn't use oil or smoke,I'd run 10W-30 or 10W-40--at the most 20W-50 if temps stay above 20 degrees..thin oil flows thru the motor faster on cold starts,and actually lubricates better than heavy oil can in many cases...can increase gas mileage some too...
I never saw a huge drop in oil pressure going from 20W-50 to 10W-30 in my GM trucks,though at idle the gauge would drop lower than it would with heavier oil...as long as your getting 10 psi or better at idle,and it goes up to 30 psi or more at speed,I'd not worry about oil pressure..I've owned many small blocks that had even less than that,none ever "blew up" on me...
