Of course the real question is....are you running a generator or a alternator?
59-61 heads are for generator...which mounts off the exhaust manifold...heads are not set up for alternator.
62 and up heads are set up for alternator.
70-71 440hp engine got the heavy rods and special balancer. 72 and up to at least 75 440hp engine also got the heavy rods, but not the special balancer. I have taken apart many 70-75 non HP 440s that were in heavy duty applications that had the heavy rods, steel cranks, and windege trays, but no...