Flywheel timing issues

[Stpndsmnn at aol.com]

I am having a little trouble timing my '83 GT,  All I can see on the flywheel 
is the 0 mark and then an advanced mark which is just a line with out a 
number identifying the degree the two marks are maybe 3/4 of an inch or so 
apart.

 Does anyone know how many degrees that line stands for?  

I guess if I knew the outside diameter of the wheel I could use that to find 
the distance between degrees and mark the wheel myself but that doesn't sound 
like a lot of fun.

Thanks
Matt Kramer
'83 GT turbo