That would be the biggest and widest mark. Are the first mark on it when turning it clockwise to the pointer.
on the harmonic balancer
The timing marks are on a tab adjacent to the harmonic balancer.
On the front of the timing chain cover, drivers side towards the top of the harmonic balancer.
The timing marks should be found on a little metal plate directly above the harmonic balancer.
If you look at the harmonic balance you will see on the front of it a medium size circle. That will be your timing mark.
there will be a timing mark on the harmonic balancer. and a timing tab on the timing chain cover. point your timing light at the timing tab and you should see the timing mark on balancer. if not timing is way out.markstang.
There should be advance marks on the harmonic balancer, and timing marks on both timing chain gears.
line up timing marks from harmonic balancer and timing tab on timing cover
It is possible that the harmonic balancer has spun.check the rubber around the balancer for cracks or decay.If so replace balancer...
4 degrees btc-before top dead center with the vacuum spark line disconnected.the timing mark location is on the harmonic balancer. this is for a 327 engine
Go to Autozone and tell them u need a harmonic balancer puller
8 inch balancer.