I recently installed a rebuilt 12A in an 81 RX7
It has good spark with brand new coils and plugs and good compression. I have got the timing dialed in so that the engine shakes and makes alot of smoke but it just wont fire. Any troubleshooting advice would be great.

 

welcome to the board.

how good are your cap and rotor? as long as you're sure the distributor is in the right place (the gear), then try rotating it a little. sometimes that helps. you can set the timing and lock it after the engine fires and goes through a heat cycle.

 

Sounds like you lost top dead center. Try rotating the distributor in plus 90 degrees and minus 90 degrees to where the engine sounds the best. It is best to just have only the leading plug of the 1st rotor connected. That's what happened when I installed a rebuilt engine.

Or rotate the engine by hand, and find where top dead center is by looking in the spark plug hole.

maybe you have the spark plug wires messed up, which I doubt, but it is a possibility.