Here's the deal. The 340 in my 1970 T/A has a strange timing issue. With #1 cylinder at TDC, the rotor points to the #8 plug wire. When trying to time it (vacuum advance unplugged), the timing mark is way off at about 25 degrees BTDC. Turning the distributor to the correct setting of 5 degrees BTDC and it will not run period. When the distributor is set by ear to where it runs the best, the car idles somewhat roughly and the engine shakes alot. The car runs down the highway pretty good though but seems to lack power. When stopping it dies almost every time. Could this be a jumped or stretched timing chain? I thought it might be a slipped harmonic but this doesn't seem to explain the rough idle and dying. Ideas??