It helps to have all the plugs out, battery fully charged (or hook up a battery charger set to high/start), and the throttle blade propped open. All of this will help with getting the maximum readings. With out doing these things the engine wont be able to crank/rotate as quickly. Your relying on the starter to turn the engine so if spark plugs are left in, the compression of each cyl will retard the starter's movement. Same deal with the battery. It needs to be up to charge and remain so throughout the test. If the starter does not spin the engine fast enough, the cylinders will not fill up properly for the test. Opening the throttle blade/valve will help to bring in air to fill the cylinders. Also, let the engine crank four or more times until you get the highest reading for that cylinder. You dont have to do the test with the engine hot, but some prefer to because it better duplicates running conditions. It is possible to have good compression while the engine is cold, but have a leak when the engine is warm.
That percentage spec I mentioned before is actually 25%. So your minimum compression readings must be within 25% of the highest reading (= or > 75% of the highest). The absolute minimum reading should be 100psi, which is why I thought your 90psi didnt sound so good. I do know that hi-perf engines will sometimes have low readings due to their cams. Im not too sure that would apply to our vehicles though. Our cams arent nearly as wild as what Im thinking that statement applies to. Ive got the same cam as you and my lowest reading was 120-125 with the highest at 145. With my bad cam in the past the readings werent too far off (110L, 130H). Try the test as I stated above, and see if your readings go up.
How is the needle on your vac gauge moving, is it steady? Also, again, how did you break the cam in
Did you follow the proper break-in instructions, and also use a generous amount of engine lube on the cam and lifters?
I would be surprised if your #s jump up drastically
, you did mention something about blue smoke didnt you? Is this coming from the valve cover breather? Is there pressure coming out of this breather when the car is running?