not at all uncommon on sv engines in any app from their introduction in late c/y '58 thru phaseout of that distributor for IH sometime in c/y '71.
And this is why I continuously ask folks to properly identify various vehicle components before asking questions or posting responses! Twenty five to fifty years after any IH vehicle was born who knows what anything bolted on might be???
Which distributor was used oem in what platform was very dependent upon how the vehicle was spec'd for line assembly when it was born, even a distributor could be part of an engineered powertrain package that is unique to just a few, seemingly unrelated order point callouts for a specific vocational vehicle application.fleet order.
Same for the delco "mag pulse" ignition system, a very rare and highly sought-after sparker made famous on the original z-28 camaro and other GM muscle products of that era. But ya could spec one onna IH loadstar medium duty truck!
I'm working with a friend right now onna '75 200 pickup. And guess what...it has a delco iron distributor mounted...so it's been swapped in at some point as the oem Holley gold box amplifier is still mounted on the fire wall.
This same scenario is seen over and over regarding Scout II platform..."most" had a Holley 1510 distributor with points, and then many with the gold box variation. But a like number had a prestolite points sparker and later a prestolite electronic unit.
Irrespective of this forum alone (the only IH-related I-net resource I deal on), there is not a single day that goes by that I don't get pm's. Emails, and phone calls regarding the subject of "what distributor do I have?", "what carburetor do I have?", "what transmission /axle set do I have?", "what engine do I have?", etc. And without part numbers, pictures, model codes, etc. It's impossible to provide correct information for that person's question! These rigs were not chryfordrolets, hell man you could order a Scout 800 "glider" if ya wanted one...or just a rolling chassis if so desired!