75-80 psi during the run, 75-80 psi in the shutdown, even hard on the brakes with my chute out.

Okay, I have had similar issues. I think many of us do not have enough drain back holes in the heads and blocks. Also we tend to run the oil on the low side and then by end of the run most of the oil is up on the top side of the motor.
You can add drain back holes in back of the heads that have a hose that go directly into the side of oil pan. You put the drain fitting and hose in the lowest corner in back of the heads.

Try running one more quart of oil. Look if it is going to zero in the shut down on the brakes in not too bad. If it goes to zero wide open you just bought a new motor.
When I ran 20-50 oil it would go to zero at end of the run when I hit the brakes and sometimes would not come back up for a while. I do not like that but my bearings always looked perfect.

I went to thinner oil 10-30 with a few quarts of 20-50 mixed in and problem resolved and car picked up a few pennies. What I have been doing last few years is mixing several different oils because I like the additive packages. I use a few quarts of the Brad Penn 20-50 because it has a lot of Zinc and Phosphate? Then I use several quarts of Valvoline VR1 Racing oil 10-30 because it was rated best on one of the tests I read. I also use some Valvoline Max-Life because it was highly rated 10-30. Thinner oil gets back into oil pan faster and that eliminated my problem.

I also run TWO of the large (1.5 quart? each)truck type street oil filters because the street type filter smaller particles out of the oil. The filters are parallel so all of the oil only has to go through one filter for less restriction.

Curly, I would caution you on mixing brands of oil. The chemicals that make up the additive package may not be compatible. You will be better off in my opinion stay with one brand if you are mixing oils. Again,just my opinion, your mileage my vary.

Had a similar problem. Took a bit of work but made up a piece of metal about 85% the size of the sump with a slightly larger gap at the back of it to help oil return. Welded that to the top of the of the pickup. This helps keep the oil around the pickup. You can also purchase this deal from Moroso - first time I came across it was on the RMS site. Kept the same amount and type of oil, no more low oil pressure in the dragster.

While we’re on the subject, what yoy guys like to use for an oil pan with a billet pump?

I have the same pump and pan combination as you on my 565. I fill the filter and put 7qts in the pan and I see the same 20-30lbs of oil pressure for a few seconds. I got this motor used and have only had the intake and pan off so far but I can tell you whatever MLS head gaskets are on it block a good part of the oil drain back holes.

quote:

Originally posted by DRB Motorsports:
While we’re on the subject, what yoy guys like to use for an oil pan with a billet pump?

I have the Moroso 21049 on 2 engines with the Moroso billet pump. No issues with that combination. Shut down oil pressure only drops to around 30 most of the time. We run 7 qts plus filter.

My other engine has a Stef’s aluminum pan. It’s a nice pan but it’s very sensitive to oil level. If it’s a 1/2 qt high it loses .05 and 2 mph. Half quart low and oil pressure goes to zero in the shutdown. It only holds 6 + filter.

In my opinion a billet pump is a requirement in a dragster. I also broke a pickup, but it fell off at about 600 feet. The motor tightened up long before the oil pressure light came on. So now everything I build will have a billet pump.