Compression test

[tsubaki]

Can't say it's correct but I usually remove all the plugs, hold the throttle butterflies wide open and pump each cylinder till the gauge levels out.
This is done using a remote start switch (jumping the solenoid) with the key off.
Hoping for no more than 10% difference between the cylinders.
Never been able to determine what the "correct compression" for each engine was. With the 150's, I expect 90psi and above is pretty good on the crossflows, I would think the loopers would be higher.