Kavesh, T.D. C. is the most common reference but if you mark the dampner after you stop @counterclock wise and again at movement point @ clockwise relative to zero on the pointer the distance will be the same. I have a 292 in my shop that is a full 4 degrees off on the scale attached to the front cover; T.D.C. is actually @ the 4degree retarded point, you may have to fabricate a positive stop from an old plug to varify your dampner&pointer. While you have the valve cover off to re-adjust the valves take a hand pump oil can and flood the valve guide on each of the intake valves; since you are without a vacuum gauge you'll have to listen for the idle to improve or the miss to smooth out. If the exhaust begins to smoke on a particular guide then you have a clearance problem there; this is effective if the o.e.m o-ring seals have not been replaced with p/c type seals. The ported vacuum signal can be blocked if an incorrect gasket is installed between the base and mainbody; I don't know about your area but most of the kits I get are universal and come with multiple gaskets so they can be used on several carbs of the same basic design...good luck....fats
