Good thought I completely scattered this. Get yourself, or make, a piston stop and check TDC
Here's my old one, I made in the mid 70's........
I actually misplaced this, for awhile, some time ago. I actually had withdrawal pains. Then one day there it was........when I'd pulled the teen outta the 67, I'd shoved it into the PCV grommet in the valve cover to plug it!!!!!!!!...............and forgot it......................