66 7 liter engine vibration after flywheel replacement

I recently replaced a flywheel and clutch assembly (reman parts) in a 66 ford galaxie 500 7 liter. the car arrived with a destroyed clutch and flywheel, even the ring gear was chewed up. I could not start the car, the owner just bought it and only had it a few days when it came apart. I had a hard time finding parts, finally locating a flywheel and clutch kit, I installed it with a new starter, everything seamed to work ok, but the engine vibrated and the owner said it did not vibrate like that before, it seams to be rotational, iI sent back the other flywheel as a core, and I ordered another flywheel and installed it in the car, the vibration is a little better but it is still there. I had a friend from a machine shop look it over and a couple of other mechanics have opinions about this car. I was hoping someone here could shed some light on my problem. I have been told that 428 is externally balanced and must have a 428 flywheel, the part store tells me that they have provided me with a 428 flywheel. The machine shop says the engine may not be a 428, and numbers at the bottom right hand side tell them it's a 332? although he told me there books have been wrong before. another mechanic thinks that the part supplier is giving me an incorrect flywheel. how can I tell what engine this is from the out side, and how can I be sure I am getting the right flywheel? the car's vin number does tell me it is an original 7 liter car. the engine does have the goodies on top, ie chrome valve covers aluminum ford intake and holly 4 barrel with cast iron headers. any help would be greatly apriciated