Pure Stock, 1970 455 Stage 1 engine compression psi?

Anybody know what the factory cylinder psi is on a bone stock 1970 Stage 1, 455 engine?

Maybe there is a Buick service manual that documents it?
I've been told it's 180 psi with 4 cranks of the engine using a compression gage.
I've seen a lot of 455's Stage 1's Dyno tested, BUT, none were 100% pure stock.

Anybody know the answer? Vet

 

I was guessing it might be 180 psi.
I told Larry the Wizard what you saw on Nick's Garage.

I'am guessing it's in a Buick service manual, I don't have one.
Thanks.
PS, I was on Nick's garage where he Dyno'ed a 70 455 Riv engine, stock at 370 HP and only got 150 psi with 4 cranks on the engine. Dyno testing on this "stock" 455 was not close to factory specs in either toque or HP, and with the powers adders, NOT any longer pure stock.
Nick had the heads milled down
.040, and ran tube headers to gain more HP and torque, everything else was stock.
The head milling added 170 psi, he wanted 180 psi.
With tuning the QJet and timing he got 400 HP and 502 pounds of torque.
Now they didn't say the cam was stock or not, I sure it's an aftermarket. I have to believe it is not stock because finding a 50+ old cam is next to impossible. My guess is, the customer bought a cam with identical or close to factory specs.
This engine is a cruiser not built for street or race application.
This 455 was a fresh rebuild, I was surprised that a Riv 455 Stage 1 only produced 150 psi.
Have to say, getting 400 HP with very little HP adders was surprising, but couldn't reach that Buick advertised 510 lbs of torque.
So, milling heads and tube headers, carb tuning and timing only got an extra 30 HP from the factory original 370 hp.
I have always wondered how the Rivera got 10 more HP than the Skylark. Must be all about buick marketing. Vet

 

I understand. The same for a leak down test.
This is the psi numbers on my
Engine.
COMPRESSION CHECK–

•dr/s:
#1—180
#3—185
#5—180
#7—175

•pa/s:
#2—180
#4—185
#6—180
#8—180

 

Generally, a spread of less than 10% is deemed good.

 

Nice to know, thanks.
Seeing my block has never been decked, I was surprised the psi spread are very close. Vet