• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

440 oil pressure too high ?

Before I did anything verify the gauge. If thats correct, put 5w30 or 10w30 in it. Pressure is just a reading of resistance to flow. 30 flows faster than 40. Thus the pressure will be lower for any given oil temp. As far as running thinner oil vs protection. Many drag cars run 0W. Personnally my 15-1 580" BB Mopar runs 5w25 The adjustable screw works fine. But I don't think it's necesary in this case.
Pressure is a function of bearing clearances, oil viscosity and delivered volume
I’m not as versed as you are reading many of your posts. Had an engine temp hassle that didn’t subside after motor break-in. I did a bunch of the usual things even thinking about a larger radiator I didn't do. 4 blade to 7, located an OEM shroud, installed a top seal at the advice of a fellow member. Latter were options for my car it didn’t have. (Nice that the seal kept the bugs from splashing under the hood.) Temp came down some; but still high with what’s typical operating temps for my motor, aside from the pref things done.

As I was researching oils and coolants, was surprised to find some reputed oil guru’s (recall Lucas as one of those) discussing high-visc racing oil, specifically when it should be and shouldn’t be used. A point was are you ‘racing’ or mostly street driving? If street driving, step back on high-visc oils. How I came across this was actually things that can cause higher op temps. It’s said that heavy weight oils can retain more heat. After installing a read-out oil gauge, watched it closer and dang, pressure was always high, even after a 50 mile drive, and barely dropped at idle. Also a higher ratio of coolant is said to increase temp. Went to a 10/30 racing oil and reduced the anti-freeze to around 30% (car is only driven during warmer weather and sits in a heated garage).

Okay, I'm not sure what all made the contributions or not to lowering op temp’s, got the desired results.
my 440 is high also. 100 psi cold then it goes down. 30W oil. It lives so I'm happy.
yes i agree, bearings are defiantly getting oiled. much better then 'not enough' oil pressure. i thought the relief valve may not be working correctly. Suppose i could pop it out and give it an inspection. i thought it's job was to limit the overall PSI as a bypass. Maybe i'm not understanding the actual function of the relief valve??

come to think about it.... i bought that pump 2 marriages ago. I'm suspecting it's a High Pressure and not HV...

i'm going to crawl under it and see if i can see the numbers.

i'm glad i asked , makes me feel better about it.
i appreciate everyone's responses!!!
You are correct in your assumption about the function of the HPRV, by relieving excessive pressure. The oil pump is a positive displacement design....it will continue to provide pressure at its design volume at a specific RPM.....until the flow goes to zero, then the pressure goes to max....until something breakes....like the pump drive shaft...its a safety device...like a fuse in an electric system. The HPRV, IMO, does need to be adjusted, the spring loaded valve spool is just fine.
To reiterate, my RS23V0A****** 1970 GTX has a high volume oil pump. The main bearings are full gtoove Clevite tri metal bearings at 0.0025" clearance (to provide 360° rod bearing oiling) with 15 #/ft more torque on the cap bolts for better crush; the rod bearings are Clevite trimetal bearings @ 0.0025" clearance. I use ARP hardware every where. My oil pressure cold is: 80 psi @ 2000 RPM, 60 psi cold idle @ 1200 RPM oil pressure HOT is 70-75 psi @ 3200 RPM cruise, 55-60 psi @ 1200 RPM....with Mobil 1 10W-30 oil with 1 pint of ZDDP. This is what works for me......others may disagree....
Last edited:
hi guys, i know it was recently discussed on someone else's thread this year but didn't want to hi-jack his thread, so i started my own. i rebuilt 3 years ago , i don't recall the bearing clearances but were in specs of the plastic gage i used vs manual, i know that doesn't help. in hindsight i should have written down the results. The engine been around these numbers since i dropped in the motor 2 seasons ago. I'm not sure if I'm just staring at my oil pressure gauge too much instead of the speedo .. i may be fine but wanted to check with the group :) any reason to be concerned with these numbers? i suppose i could swap with a stock meling ...

autometer , electric gauge
440 / 727
meling high volume pump & 7 qt pan.
brad penn 10w40

start up / cold idle in park 80 psi

hot numbers
idle in park 45~50
idle in drive 35~40
cruise @ 60 mph (2800 rpm) 80-85 psi
cruise @ 40 mph 70-75 psi
@ WOT i can see it hit 90

thoughts appreciated.
- hubba
GOOD OIL PRESSURE PER THE CHRYSLER racing manual u need lbs of oil pressure for every 1000 rpms under hard throttle can rev the 440 to 8000 rpms but i wouldnt go past 6500-7000 now driving on the road u will never get that high of rpm
now dinr do anything to he motor u have good oil pressure . most guys have to buy a race pump toget oil pressures that high /good . now what ever u dont do is restrict rhe oil flow u will regret it (}its called oil starving / blown motr .i know of 2 mopar raceing guys tthat restrict their oil pressur to 65 psi but they r pushing the 440's -=to 7500 rpms they have blown 2 bb mopras &W they say the mopar engineers didn.t know what they was talking about / i run a 400b to 6500 with 95 psi in 13 yrs of racing i never oil starved a motor i have another freind he runs 115# of oil hes getting 168 in the 1/4 hes been doning i for 20+ yrs with out a oiling related problems