New head, timing correct no start

Mazda MX3. 4cyl standard, 1993. Had a bad head, pulled head, bought one from junkyard, put it in, no start. no holding compression, took it to machine shop. bent it back into place, valve job, cleaning, resurfaced. put in re-done head, timing correct, new spark plugs, new dist and rotor, gas, has crank but no start. battery low and old. haven't checked compression but really frustrated. AHHHHH any suggestions? where to begin?

ok back to the basics, you probably already know this but think simple man..

Spark - pull a spark plug wire while a friend cranks the motor. Do you see/hear it sparking? If no, check the disty. Also double check the firing order and your spark plug wires.

Fuel - after cranking the motor for 3-4 seconds, pull a spark plug, you should be able to see/smell fuel on the tip of the plug. It should reak of fuel so it doesnt take a strong sense of smell.

You said timing is ok and air... well air is almost a given.

When it turns over do you hear combustion? or nothing at all?

if it tries to fire but dies right away check the plastic snorquel between the air sensor and the throttle body. That sensor picks up the tiniest leaks and shuts'er down right away