Correct Cyl pressure for a stock 72 440?

[74norton]

I am about to increase the CR of my stock 72 440 via milling the heads. Before I do this, I want to make sure that the bottom end can handle the increased pressure. If the bottom end is worn, I am going to do my CR increase by replacing the dished pistons instead of milling the heads.

I am going to do a leakdown test as well as a regular compression test. I know the 75% rule when it comes to testing the compression, but I am curious as to what a good cyl pressure for the motor is. I am guessing it will be anywhere between 110-150 psi and expecting it to be somewhere in the middle of these.

I need to have a good estimate of what the factory pressure or a good solid pressure is so I know at what point should I decide to abandon milling the heads and just go with new pistons.

If I do go with the new pistons, once I pull the engine, am I going to end up going through the bottom end? New pistons will require an overbore and thus removal of the crank, the engine is pretty fresh and has been used for light street duty, no racing etc. Do I really need to magnaflux the crank have it line bored etc etc.?

Thanks for the advice
Charles

70 RR 440 4 speed
76 volare (former grandma car)

[jimbo7074]

Assuming this is an 8.2-1 stock engine I would say 120-130 psi if in good shape.

[6pakman]

ditto here, 130- 150 concidered very good.