Like Camaro69, I'd be looking at the valve adjustment. Your brief description of how you adjusted the valves doesn't sound right.
In the 2-step process you first rotate the crank until the piston in cylinder #1 is at TDC on the compression stroke and then you adjust half the valves. Then you rotate the crankshaft 1 turn and adjust the other 6 valves.
If you adjusted all the valves with the crankshaft at one position, well, that's the problem.
BTW, where did you get the "brand new heads?"

 

I did adjust the valves in the 2 step process at #1 tdc adjust 6 then one more revolution to #4 tdc and adjust the other 6. I purchased the heads at a local part store. Thanks

 

If the valves are not set right then a compression test is not going to show accurate info. I would personally retrace the steps of the valve adjustment. Put the #1 on the tdc of the compression stroke and adjust both intake and exhaust. Move the crank until the next cyl is at tdc and then do that one. Rinse and repeat 4 more times. It is really hard to tell what valve to adjust in the 2 step method with the intake on. Doing the 6 step method here would show the best results.

Just askin here to help us help you. Did you replace the head bolts? Did you just torque them or did you torque them and then adjust the angle as well?

Massey

 

I realize this is an old Post... really old but if anyone has this issue and has been searching for an answer this is what to do.
One day out of nowhere I went to start it up and it was popping snapping backfiring I was wth?......
Unplug the cam sensor the car will fire right up long as you haven't flooded it then plug it back in once it's running. I had the same experience and come to find out my timing chain was to sloppy and causing this very issue weird thing is the car ran the exact same way plugged in or not lol.
I replaced the chain and all was well.