Lack of compression could be from lack of seal of the rings or the valves. A leakdown test will reveal where the leak is located. You put air in the cylinder and listen in the intake and pan for hissing. If its in the intake or exhaust manifolds you have valves leaking, if its in the pan you have ring seal failure.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.