As exhaust valve is 3/4 of the way from closing, the intake valve starts to open???

[pwrunt3pte]

I replaced the head gasket on a generation IV 454. after i had it back together it wouldn't start. you could tell there was something wrong because the starter didn't have that usual sound to it like there was no compression. i noticed that when I cycled the engine around with a breaker bar that the intake valve would open, before the exhaust valve had closed all the way. Meaning that they were both open at the same time for a second. I didn't touch the cam, timing chain or gears when i replaced the head gasket. Is this a valve adjustment issue or is the cam miss aligned?