[mike nixon]

Very rarely will a cam lobe affect compression unless the cyl is being washed with fuel.

I'd suspect a burnt / corroded valve or seat or broken valve spring, or stuck rings, before a bad cam.


If it's rings dump rislone in it and drive it, they may free up.

Valve springs can be changed on the car.


Before you go digging too deep be sure the ignition is firing correctly on that cyl as an ign miss can wash the cyl down with fuel and lower compression.


The 396/402 was one of the best v-8's chevy built.

Mike


Mike

[Tin Injun Tom]

I agree with sleepy, on the valves and rings being good. It should fail the leakdown test if the valves are burned.
Are you 100% sure of the leakdown? The reason I ask is this:
Alot of compression testers, including the kind AutoZone sells, have a release valve on the gauge manifold. Until you press it, the gauge will "hold" the final reading. I think there is a one way check valve in there that lets the pressure build up, but doesn't allow it to escape. It fooled me into believing the cylinder was holding pressure until I thought about it. I think it was when I unthreaded the hose from the spark plug hole and the gauge still read ***lbs that I realized it wasn't going to work for leak down testing.
Disregard if you know you did a proper leakdown.

A bad intake lobe on the cam for #6 cylinder could very easily cause low compression.
You didn't say what the pressure actually peaked at though. Did it take more cranks than the others to get to peak psi?