[66sprint6]

Since I'm unable able to get the parts I need to install our Round Port engine in our '67 LeMans, I've been trying to improve on the overall performance of the engine that is in the car now. It's a 400 engine from a '74 vehicle.
It ran poorly when we got it, but I changed the plugs and wires, switched to HEI, made sure that there were no vacuum leaks, etc. It runs much better now, but it's not quite there as far as the idle and power are concerned.
It's got good compression and it seems equal across all cylinders. It also has decent vacuum. The timing is good. So I'm kind of stumped as to how it feels like it's got less power on one cylinder or something. When it idles theres a bit of a shake to the car.
I'm wondering if the problem may be the camshaft. But before I go and tear the engine apart, I thought that I should check the intake and exhaust valve lift on each cylinder, to see if they are equal. I'm thinking that this would also tell me what cam is in the car with some calculations.
At first I thought that a simple dial indicator, mounted to each individual rocker would indicate the lift. But I then realized that with hydraulic lifters, the valve spring would overtake the lifter and keep the rocker from coming up. In this case, is it possible to undo the rocker, push it aside, and put the dial indicator on the end of the pushrod? What do you think? Is there another way to check if a lobe on the cam has been diminished?