My recently aquired '87 Sub 6.2 runs really well, doesn't smoke at all, and is quiet cold or hot. So why when I'm riding around does the oil pressure appear to drop? I noticed it as low as 5 lbs, and the needle seems to respond to RPM, so I sorta trust it. I thought the oil pickup might be blocked with sludge, so occasionaly I'll turn the engine off for a few seconds, then re-start. All while going down the road at 60 mph. I filled with Rotella syn 10W40, AC Delco filter. Oil was clean after 1000 miles, a sign of frequent maintenance. Odo shows 70k, mabe 170k. Temperature is below freezing, runs 200f. I will change sender, and might install a quality mech guage. So my question is, does somebody make a HIGH VOLUME oil pump? Melling lists only the standard unit. I would also install the steel shaft.