timing questions for '68 318

Are you using the original parts that came on the engine out of the factory, or did you piece together parts. If you don't have the original timing chain and harmonic balancer, that could be your problem. they changed the timing marks on the timing chain cover and harmonic balancer from 69 to 70. If you have mixed parts from the pre and post 70 engines, your marks will be off.

the easiest way to correct this is to put the engine at TDC and make a new mark on the damper that lines up with your TDC mark for your timing chain. Use white paint or white out and make a nice line across the damper that line up with the timing marks already on the engine. Also paint the timing marks on the timing chain cover/bracket for timing marks white. this makes them much easier to see when you are using the timing light. Silver also works well. Basically this method you are resetting your TDC marks for your engine parts.