Was driving down the road when there was a loud bang from the engine and then we coasted to the side of the road. Got it towed back home and here is what's happening...
Distributor is no longer lining up like it should. It's almost a quarter turn from where it used to be, where the mark on the rim of the distributor for #1 used to sit when it was correct is now where #4 fires. Still spins though when you turn the main pulley.
Noticed also that when the pulley turns the valves are not opening up. there is no movement from the rockers at all.
We puled the engine and stripped it down, pistons and connecting rods are all intact, the valves are all fine and none of the push rods are bent so i'm fairly certain i'm dealing with something inside the block.
Any advice, i'm breaking it open tomorrow but haven't done internal engine work before so any hints on what to look for.
Appreciate any assistance