[johnpro]

On a true '66 timing chain cover, it'll just be a little nub sticking out, with what looks like a screwdriver blade (flat head) on the end. Sometime between then and '69 (don't know exactly when) they switched the covers, and they started using a bolt on timing mark with an arrow that is flat and actually protrudes over the balancer.

You may have the later chain cover without the bolt on pointer (my '66 is like that). I recently acquired the correct '66 cover and will put it on when the engine gets transplanted to my son's car in a couple weeks.

If you always do what you've always done,
You'll always get what you've always got
http://www.classic-mustang.net/johnpro
http://www.classic-mustang.net/john66/mustang/pics/66fsides2.jpg

 

[johnpro]

I just use my timing light to see how much total advance I'm getting and when I have it fully in. The initial is always set by ear.

Unless the dampner is new/rebuilt, there's a good chance the marks are off. And besides, timing specs are for totally stock engines, and even then they're the engineer's best "average". Start adding things like cams, tuned intakes and carbs, under-drive pullies, high output coils, and such, and all those factory specs go flyin' out the window!

If you always do what you've always done,
You'll always get what you've always got
http://www.classic-mustang.net/johnpro
http://www.classic-mustang.net/john66/mustang/pics/66fsides2.jpg