[firebird74]

Hi all. Just hoping someone on here can answer what may be a very simple question for me. I have just recently built a pontiac 400 but never replaced the oil pump (i know what a tight arse) well the obvious has happened and the oil pump started failing so I have replaced the oil pump with a new high pressure one. Now this is where I need help, I've been told by several people that a high pressure pump is bad for a stock 400 because it will force oil into places it shouldn't go, will blow off oil filters under hard driving, etc.... never any good news. The oil pressure at the moment is, on start up from cold it will climb to 85 - 90. When warm and driving at around 3500 - 4000 rpm it can go upto 95 and at 2500 - 3000 rpm will sit at around 70 - 75. Is this okay or am I doing more harm than good

[superdutybob]

My first question is this: Where are you getting these pressure numbers from? If you are reading a stock, in dash gauge, I feel they read high. You need a mechanical gauge to get the most accurate reading.

As far as high pressure hurting an engine, yes it can somewhat but it depends on what oil you are running and at what outside temperatures you are driving in. Thick oil+cold engine+high pressure pump= blown oil filter seal, twisted oil pump driveshaft, etc. Maybe not all of them, maybe all of them, maybe some of them. No guarantees.

My recommendation would be to run the mid level RA pump which is stated as a 60psi. I would not run the 80psi SD455/RAV pump. Takes too much horsepower to run it and the above issues may occur.

HTH!

[2manyT/A'S]

As SDB says,stay AWAY from the 80 psi pump.

I've seen them SNAP the stock oil pump driveshaft.

Just run the high volume pump (60 psi) which should have been standard on 400 & 455 Trans ams.