thanks for info! really appreciate it! have a great weekend!

if its cummins remember the little oil cooler on the back of the oil filter. could be cracked. test that before you go ripping the rest to bits mate

cummins engine:
Engine Compression
2944 kpa
427 psi

It is recommended that the compression pressure be checked and compared on all cylinders. All cylinder must be within 276 kPa [40 psi] of each other.

GM 4.3 engine:
"Install a compression gauge. Hold throttle open and crank engine with starter. The minimum pressure is 690 kPa (100 psi). The lowest pressure in a cylinder must not be less than 70% of highest pressure."

This is straight out of the hyster service engine section and it does not give a definitive pressure reading on the GM other than in that statement above, at "least" 100psi and there should not be more than a 70% difference between them.

190 plus or minus 25.