It will like it.

If I was bored (& had plenty of time) which is the story of my life I would get a guestimate on the CC's of 906's milled 30 & an average HG thickness & the supposed zero deck & plug it in the the KB pistons calculator site (its a fun tool) & there there should be a site or chart somewhere on the SCR that would produce those kind of numbers then see what piston dome it would have to have to achieve that. that'd keep ya busy till you confirm with another gauge and or open it up (first I'd borrow a borescope). Keep us updated. EDIT At least I would see what dome/CC's would be needed to get 10:1 which is what they came up with & they did mention zero deck so likely they did measure everything.

Just for comparison, some of the "better" FAST type builds I've been involved with pump around 240-250 and more.
Those are 14:1+ compression with very fast rate solid roller cams.

Russ, did you ever check the cranking pressure on your 505?

My friends stock eliminator motor is 205-210, and my 383 was around 200 the way it was in the car.
Lowered the cr from just under 11:1 to 9.7:1, and went from a 106lsa cam to a wide lsa cam with a later closing point and the cranking pressure dropped to 155.

I played around with the Wallace cranking compression calculator.

It seems "highly unlikely" the motor is 10:1cr with the 484 cam, cranking 240+ psi...... Or the gauge is wrong(or maybe a little of both).

A 10:1 446 with the 484 cam installed at 104 should pump 156psi at zero feet elevation.
Assuming the duration is actually "284", and a 104 c/l, the intake closing point is 66abtc.

Changing that number to "0", only moves the needle to 212psi.
Changing the cr to 11:1 with the closing point still at "0" shows 240psi.

Assuming the cam is installed correctly;
14:1cr shows 237psi
14.5:1cr shows 248psi

I also plugged in the numbers from one of the FAST motors that pumped high, and it showed 240psi.

At this point, the gauge is still suspect in my mind.

Lash @ 0.025 = 190 - 195 psi
Lash @ 0.014 = 175 - 180 psi.

10.8:1 CR.

But probably have an actual intake closing point of 78° to 80° ABDC.

I think there is a lot of merit in the bled down lifter theory. Always kinda questioned getting an accurate compression test with today's hyd. lifters in general.

Using the Wallace calculator, even assuming the valve is closed for the full 180deg of the compression stroke(which is saying the lifter bleed down makes the cam 132deg shorter), it still only showed 212psi.
Even with the lifters fully collapsed, I'm not sure the intake closing point would change by 66deg.

I'm pretty confident the lifters are at least partially collapsed, but not enough to add 100psi to the compression test.

I think there is a good chance the gauge is reading a little happy.

Just got engine running. I ran it for a few minutes then checked compression. It was at 195psi average on all cylinders.Turns out fast68plymouth was right on lifter theory. Thanks again.

So you think that everyone else was an idiot ?

No of coarse not. Why would you ask that? Everyone that replied had valid points. fast69plymouth point just happened to be correct.

I missed something, If you dont mind, what made the psi reading come down from 250 to 195? I did not grasp the lifter post.

1st page 11th post.

Got it & I learned something

I've actually been right about a few engine related issues once or twice before

Glad it seems like it's worked out for you.

We noticed (& are appreciative).

Fast68 - please check for a PM from me.