ONE way to tell is to look for âC7707â cast into the underside of the exhaust side of the headâŚit would be in the sand-cast rough area between two of the machined surfacesâŚeither the forward area, or the middle area. From what Roger-Down-Under has found, that late of an engine number SHOULD have a rather large âCâ cast into the spark plug valley of the headâŚcanât miss it.
The next section forward is where the âC7707â is cast on my headâŚbetween the flats.
And also is close in engine number to my G5705-8S, BB435, RHC 8, C7707 C3. This head does have âCâ cast in the middle of the plug valley.