All this talk reminded me that this happened to me in 1991.
I had a short block assembled at what should have been a respectable shop...Was charged on the invoice for degreeing in the cam and everything...
This was a dirt track 340 motor with a 284-484 Mopar Performance camshaft.
There were 3 marks on the timing gears the triangle...the square and the dot. They lined up the dots but the dot on the outside of the crank gear wasn't stamped well.
After two weeks of no RPM's...Changing intakes and carbs and distributor I pulled the timing cover...
Instead of the crank keyway being at about 2:00 and the cam at 4:00 and the dots aligning the cam was at 4:00 and the crank was at 12:00. The dots were aligned but it was the wrong dot on the crank gear.

When I pulled the "X" heads after finding this it had lightly hit the valves...
I remember that motor had a very small sweet spot where it would start easy and if the timing was off just a little it wouldn't start...
Worst thing about getting old is the things you forget... frowwn


...FAFO...