1968 340 harmonic balancer and main pulley

Thanks for all the information and input.
Anything is possible, but I am doubting anything is terribly mismatched i.e., having the old engine’s (360), harmonic in this set up. I bought the engine from a very reputable business owner/friend and high end Mopar guy that I’ve known for over 30 years. He told me the engine was rebuilt to factory specs by Ronnie Keselowski, former NASCAR driver/mechanic from Auburn Hills, MI.
I looked at the photo of motor when I bought it (3-4 years ago) and it had a harmonic balancer and main pulley on it.
I have had several real reputable mechanics work on my car and none ever mentioned anything as drastic as a wrong harmonic balancer. The last one said I should get a new harming balancer and pulley to smooth things out.

I just want to make sure I am buying the right parts and all because of the differences I had to deal with in putting a 1970 340 TA 6 pack motor into a 68 Dodge Dart.