Wait to see if someone corrects this information.
What width fan belt do you need?
If it is 3/8", you could use any 1953 and later Chevrolet 235/261 6-cylinder 3/8" harmonic balancer.
Earlier 235 balancers would use the same fan belt width as your 216 (about 1/2" to 5/8"?).
Also, I think same car balancer/pulley diameters were smaller/different than on a truck. This would probably not be a problem for your truck/alternator.
