Harmonic Balancer Recommendation

[money pit]

Can anyone recommend a harmonic balancer for a 1978 360 engine. I have a vibration in park and neutral, and at  at about 3000 rpm. The motor and trans mounts have just been replaced (quality parts) The torque converter weights are in place. The engine was rebuilt about 3 yrs ago and the crank was balanced. I checked the harmonic balancer to see if it shifted. I checked TDC with a TDC tool (in the spark plug hole). TDC matches turning the engine both ways. I don't think the balancer was replaced when it was rebuild. I was going to start with the balancer before going deeper. There are so many balancers on the market, I don't know what to buy. Thanks

[Ramman]

Has this been an issue for the 3 years since it's been rebuilt, or did it just start this?

[money pit]

I don't drive the car very much but I think it did vibrate since the rebuild, but not that much. I remember talking to the builder. He told me he almost forgot the 360 was externally balance until one of his guys reminded him. Shortly after the engine was installed, I  replaced the rear end, the leaf springs, and the drive shaft.  It seems these changes have amplified the problem.  I'm also having the pinion angle and the posi checked (posi makes a clicking sound). I'm ready to put the slant six back in. lol

[73_Cuda_4_Me]

You stated the TC has weights on it, but you don't happen to have an external balance flex plate as well, do you???

[money pit]

I have the original flex plate.