1968 340 timing

Another potential fly in the ointment.

A late balancer/early timing mark and vice-versa

I FULLY agree with putting your finger over spark plug hole and bump until you find the compression stroke. Look for the timing mark on your balancer wherever it may be as you begin to feel pressure. Timing tab on drivers side of timing cover, should be in the 10-1 o'clock area looking at front of engine. Over pass fender if timing tab on cover are pass side, then 5-7 o'clock.

If you have a mismatched cover/balancer... that's gonna make things difficult and you need to remark the balancer to time your engine properly.