New Cam/heads and it wont start. Help!

[PGSigns]

Recheck the firing order to ensure they are all good. Now to verify a timing mark with a stop you insert the stop and turn the crank by hand till it touches. Put a mark on the balancer and rotate it back around till it touches. Put another mark. The spot in the middle is zero. Use this mark to align a timing tape. Then use the timing tape to see exactly what the timing is doing. That will help you get the initial timing correct and tell what the hei is doing as the rpm goes up. A timing curve that is out in left field will cause all kinds of issues. Now we need to talk about fuel pressure. Much more than about 4 psi at idle and 5 while running will make it unhappy.
Jimmy