If it's a smallblock, it's an understatement to simply "pull the pump". The job sucks in a door car, at least in mine. Especially if you just got it final assembled. Good luck with it.

tell me about it

Yeah, I know. Pull the distributer to allow tilting of the engine to keep pressure off the center link that goes through the pan. Pull the headers before removing the pittman arm and tie rod ends. Of course, this is after removing the front wheels. Then, everything is done on the back, including recentering the 340/360 oil pan spacer. Plus, the pan is so big, there isn't much room between it and the trans. I'll pull the motor next time, all that is left is the converter bolts. Doing it on the engine stand is a H E L L of alot better deal. Like I said, GOOD LUCK

OR you could eat a slice of pizza while you pull the pump off your big block...OK maybe two slices

Finally broke in my 360 today with a Melling HV pump and 15w/40 Rotella. 100 lbs of pressure for about 30 mins then it started dropping off. After about 90 mins of run time I'm at 75lbs of oil pressure at 2k RPMS

The HV72 I put in my SB put out 80psi in March when I first started it.(45deg) Now after a couple hrs run time and a couple passes it is 62psi@2000 and 45psi at idle (1150 rpm@ 70 deg.) Oil is 10-30 Mobil 1.

d.c. i just experienced the same thing with my samll block and got black flagged last weekend when oil squirtted past the oil filter boss gasket. i had gotten the pumps straight from melling with contingency, (also talked to a couple of other mopar racer with this problem) called melling and asked if they changed anything on these pumps and they said they were not aware of any problems, so let's make them aware of it! call them and ask them what going on and maybe they will look into it. tech guy said most likely bypass valve stuck! dave

so how is it you guys are missing this BEFORE you drop the engine in the car?
i always prime engines while on the stand so there's no surprises afterward.

I had the EXACT same "runaway oil pressure" problem last season with a freshened smallbock and new Melling HV pump. First time in all these years that this has happened to me. I replaced it with another HV pump (this time it was a Speed Pro but anyways) and problem solved.

BTW, the bad pump did not show any particular problem when I dissassembled it after removal (and I had opened it up/inspected it prior to original install). It had to be the relif valve but I could not prove it to myself so in went he new pump.

I feel for ya on the job ahead .... I think in hindsight, pulling the motor back out would have been easier than dropping the pan in the car

WHAT ????
YOU HAVE THAT BACKWARDS
30 is 30
10w 30 10w 40
5w30
it is a 30 w until the temp starts falling
below the 32^
then it stats to act like thinner
wieght for easier starts in winter
i used to spec out oil for trucking companies
desil oil have certain properties to help in sludge/ breakdown additives and soot control

Thanks for all the input guys.

DRAM, First off We primed it on the stand with a gauge attached. It showed 75 LBS. constant with a high torque drill. Don't know what else to expect

Last night I drained the Rotella and this morning tried a 5w-30. As the motor warmed up the pressure fell to about 75 at idle and was around 85 at 3500-4000. It looked as if it would continue to fall as the motor got hotter. I had the temp up to 160. Of course that's not necessarily the oil temp but it seems to prove as the motor gets warmer the oil pressure is falling into place.

The old oil pump stated at 65 regardless if it was hot or cold.

oil filter 101
if you see 85 -100 psi at youre gauge
that is about normal race car
some motors are restricting the top end ,either in the block or heads?? so you could see increase of pressure that way
youre gauge is usauly last in line to see pressure
pump does accumulate most of the pressure rest is generated by mains cam bearings?
as for filters they are restriction as well
the race filter are far less restricted than that of normal cars
reason not much filtration inside in other words it allows more oil to thru mmm
after idle the filter doesnt filter much oil at all and at speed say above 1500 rpm very little oil actually goes thru that filter
the filter cannot accept that flow
so it bypasses it altogehter
in passing a race filter filters out less particules than a reg filter does
but will allow more oil thru it faster rate
reg filter will filter more smaller particules
thru it but allow less oil thru it
does it matter ??
so long as you filter doesnt burst
??
not telling you to run cheap filter
not telling you to run the best there is either
with alcohol you have to be carefull as some dont like the water condensation