After a lot of messed up weekends I am going to BIR for a test day. I hope to have a great weekend, without any breakage.
I do have to admit 90 percent of my troubles have been maintenance related, or overlooking stuff. Some of it not obvious, some of it left too long Anyway, New EZ X Isky lifters, bigger cam, new rear Big Gun shocks, lighter rear springs, all rebuilt fuel system with new lines and hoses, and a converter that is a true 6200 stall, not as loose as I thought I had, but not 5600, which it was! I also installed a data recorder, which doesn't lie like other forms of observation.

Good luck Greg! If I tow my junk to Cedar Falls this weekend I hope I get the 9.xx! Should be some good air!

Good-luck Greg and Ted. Have FUN, go fast!!!!!!!!

I trust you verified you had pushrod oiling this time when you primed the oil system.

Yep . Oil flowing out of every pushrod.

Good luck guys!

Good luck to you too!

Update; Friday test day started with a poor run, a bad miss, and very poor ET. Also 40 psi oil pressure at the stripe. Add in the 10 psi vacuum reduction, and I probably had 50 psi. Back to the pits, first thing is check the lash. All good! Happy about that, but I still have a severe miss to track down, and low oil pressure. I found a way to block oil to the valve covers by stripping the aluminum part off some small pop rivets. They were the right diameter to slip into the feed tubes inside the valve cover and the ball on the end blocked oil at the compression fitting.
I changed plugs, put on new distributor cap and rotor. Just before I went to start the motor, I remembered that In the past after replacing braided lines, I had trouble with junk blocking the nozzles twice. I found one bad nozzle, put in a new one and warmed up the motor. I have the throttle stop set at about 5,000 rpm on the brake, and the motor didn't skip a beat, sounded perfect. The only thing wrong was the oil pressure is still too low, only 40 psi max at 5,000 rpm. Even if you add in the vacuum in the pan causing the pressure reading to be low, it still would not have over 45 psi. I figure it should have at least 55 to 60 psi minimum hot. So that is it for this year. I will have to get some advice on how to limit oil flow through the lifters. There are two feed holes in the lifters, one on either side of the lifter ninety degrees from the .060 hole I drilled in the lifter bushings. They look huge for the job. When I primed the motor with a drill before firing it, I did it without rockers in place to make sure I had oil flow in the pushrods. I was surprised at how much oil was coming out of them, and that was with cold oil. So I will start a post on restricting oil flow to the lifters.

Ted, hope the weather is as good down there as it is hear. Yesterday the barometer was at 30.04!

Getting a light shower here now. It isn't showing up on radar. Had a bad day yesterday. My wire slipped of the center post of the neutral safety switch so I picked up a used pigtail for a 727. It was pretty old so needless to say I snapped off the center wire trying to push it onto the switch. Tranny pan gasket is leaking again and I think my pump seal may be bad. Found an oil leak up on top for the oil pressure gauge. That green Brad Penn works great for finding leaks!! I have to get the car down to the 727 guru but probably wait till spring. Maybe next year will be better for all of us!!

I was told by Tim at Comp to JB Weld, shut, close up the hole nearest the oil galley on my non bushed 400 blocks on my AMC lifters from them that are made for pushrod oiling I didn't, I closed up the other hole I had Manton put a .060 rstrictor in those pushrods and I haven't primed or tested that motor yet

Why would you subtract the crankcase vacuum from your oil pressure reading? Your oil pressure gauge should show actual pressure relative to the atmosphere. If your crankcase vacuum increases flow from your oil galleries into the crankcase it will just draw down the pressure a little but the pressure reading is still valid. More volume or less flow through all the exits, your choice (or higher viscosity oil).

The actual pressure differential if there was no vacuum in the system versus 10 inch of vacuum would be the same. Notice I said DIFFERENTIAL. Atmospheric pressure against the exterior of the gauge will reduce the reading.Both the pickup and the pressure side of the pump are inside the motor, but the gauge is outside, and the difference due to the vacuum pump pulling a vacuum creates the difference in pressure reading.
When I tested the motor against the brake at a throttle stopped steady rpm, I could see the oil pressure drop as the vacuum went up.

My point was just that your reading was valid regardless of what causes it to read that way. Your vacuum acts somewhat like looser clearances would. And there's a big difference between 10 inches of water or mercury and 10 psi.