Original Compression of the 340?

[challengermaniac]

I am curious as to what the TA 340 cylindar compression was when they were new as I'm trying to determine how tired mine may be.  I don't have the equipment to do a leak down test, but here are the simple compression numbers:  Left side: 1: 125, 3: 125, 5: 145, 7: 135  Right side: 2: 135, 4: 150, 6: 125 8: 140

Also, what test is performed to determine if you have an operational cooling leak (less coolant after running, with no signs of it coming out the cap or overflow)?

[Chryco Psycho]

the original compression was 10.2 so approx 150 lbs
any variation of 12-15% is time to tear down

[femtnmax]

what test is performed to determine if you have an operational cooling leak (less coolant after running, with no signs of it coming out the cap or overflow)?

Leak could be alot of things. A slight amount of leakage past the radiator cap will sometimes not be easily noticed.  Inspect all spark plugs, are any of them more "clean" than the others, meaning a head gasket is starting to go.
Check all hose clamp connections, any white powder build up around end of hose is a leak.  Inspect the radiator, but a slight leak can hide itself because the leaking coolant will evaporate off the hot radiator when engine is shut off, so remove radiator and have it tested for leaks.
The heater core is another good place for leaks that won't show up easily.  If you have a good nose you can smell the seeping coolant inside the car while driving.  Bypass the heater system with a short hose at the water pump and see if coolant loss goes away, or remove heater core and have it tested.   These are just a few ideas.

[Chryco Psycho]

check the studs at the ends of the heads that hold on the exhaust manifolds