It started up drove fine for a day after a head change . Parked never started again. I got spark I got gas fuel pump is pumping to fuel rail it's not security feature. I'm at a loss I feel I have checked everything . Please help. The distrubutor has spark going in and out possibly ignitor the rpm guage is not jumping at all both starter and gas relay are good...thanks

 

Check the mechanical timing. It may have jumped a tooth or so. If it's ok then run a compression test.

 

It wouldn't hurt to check the ground(s) on the drivers/left end of the plenum to be sure they are tight as well.