Find a balancer for a 1954 216. It has the narrow belt. The people who rave on about the supposed 216/235 balancer differences are a little hard to understand, with the seat of their pants covering their lips. Inline six engines are inherently balanced- - - -they could run without a damper at all and have few, if any issues.
Jerry
There were no 1954 216s.
My seat of my pants are not covering my lips. You you should look for a 1953-1955st truck engine balancer. I am not sure that a car balancer from 53-54 is the same diameter, but it might be (I'll look it up if you ask - I will not make fun of you or others). They would be the correct diameter and they would have the 3/8" belt-groove.