sorry yes we intend to do this aswell, our machine guy performs this as part of the job when he checks/skims a head anyway

The brakes have really reduced in perfermance latley and after creating a false vacum its clear that both brake servos are knackered.

but also we know the vacum it not as strong as it should be. this is one reason for testing the compression.
unlike modern cars which pull from the inlet manifold (i.e all 4 cylinders)
the aston takes its vacum from one of the 3 carb bodies. so buy checking a 6 cylinders we should be able to see if its the head gasket causing most of the loss or wether its a combination of this and the fact it draws from one carb.
im guessing 1-4 should be about the same. and possible 5. and 6 should be less as this is where the oil is weaping from the gasket down the block.
also with the comp test as well, we should be able to gauge a rough idea of the state of the piston rings across the 6 cylinders, and compare this to the leak test results.

basically for the sake of a few tests, its worth it. it should give us an insight into whats going on inside, before we rip it open.
Also when we build it back up and do a second test we then have fiqures to compare it to.

Dont forget its an aston engine, its bad enough when u say the word cosworth when ordering parts. when u say aston the price tripples.

So can anyone help me then, i need to know what the compression test fiqures should be please.