aintskeered,
• Since you just replaced the heads, recheck all the engine bay ground terminal, there are approximately 8.
• This has happened to me. I recommend performing a very thorough inspection of the coil wire and it's terminals. I have had them look "normal" at a glance but the terminal had slipped off the wire core and was not transmitting any energy. Also the terminal may not be all the way onto the coil or distributor posts, I've done that too.
• I have also had the wires come loose in the coil harness; so also worth a careful thorough visual inspection.
• If those terminals and harness parts check correct, then there is balast resistor on side of the coil. If it dies, the engine WILL NOT START. Last one I bought, 16 months ago was from Schucks/Kragen/Orieley's for $4; it was not for this engine but for an older Ford, looked identicle, so I tried for $4, started immediately).