Just cant get it tuned right 440

I recently had a similar problem. Timing was all over the place, and I was chasing my tail with the carb. After a year of that I decided that I wanted more cam any way. While putting it back together I a friend of mine (who is an engine builder) picked up the timing chain, and was looking at it. What he discovered is that the chain did not fit the sprocket, the tooth spacing and the chain were different. The timing set was a Comp piece that was only a year old with only about 600 miles on it, so I know that it was not stretched or worn. Long story story short the engine was literally hunting for correct timing as the chain would grab whatever teeth it could as it turned. I replaced the Comp POS with a piece from PBM, degree'd the new stick and went back to to basics with the carb to start over, and now that thing is a monster. As for the timing mark bOb is right. Timing tape just flies off. I made a sheet metal tab and tacked it to the timing cover once true TDC was determined, and a good digital advance timing light will show you where your timing is at.