Miles,
I have dine this and the rate if the same this is what I meant in my original post when I said I plugged the air ports and the pistons fell at the same rate. Unfortunately I was unable to work on my car when I got home, I came down with guillain barre syndrome and have been in the hospital for the last 5 days, moving to rehab today fr about 10-14 days and taking this term off school for physical therapy. So the good news about all this is that I will be able to devote a lot of time to my 240 in the next few months.
Again the pistons drop at the same rate when I do this test but once I put them on the car, fill them with fluid, and replace my dampening rods they no longer fall at the same rate, the piston with the smaller dampening rod cylinder falls much quicker than the larger on, I have swapped the rods and this stays consistent. I have an efi setup sitting on the side but missing a couple things for it like the larger fuel lines and the refi relay, I would rather get the car running with my carbs before I think of swapping.
Should I take the dampening rod cylinder and have it machined down to the same size as the smaller one?