I've done everthing to try to find the vibration, and I'm just wonderiing it's a 72 340 with a forged crank (interanlly balanced) could it be that (1)I have a torque converter that has balancing weights causing the problem or (2) the harmonic balancer is drilled for balancing, and maybe it is the wrong one. I have heard that the 72 is the last year for a forged crank and sometimes the harmonic balancer and/or torque converter were mis-matched in rebulid (maybe that's me)
