So, what is the optimal

[old grouch]

vacuum reading for a Valk?  What is the optimal compression reading?  How much variation is acceptable in the compression reading?  I know somebody out there knows this.      TIA, Stan

[Robert]

Compression should be in the 155 to 165 range, evenness is more important than pressure. Vacuum should be around 15 inches vacuum is going to be harder because you measure one cylinder at a time and have to smooth the pulses. Again evenness between cylinders is more important than the actual pressure of course if you have 95 then there's a problem

[old grouch]

Thanks, Robert.  Stan