I got the info from a retired foundry engineer who spent 30-something years working for International while I changed the engine in his motorhome. He and his wife had their 50th. anniversary while the rig was in my shop. He described the casting process for the blocks, and forging the crankshafts, in pretty good detail. Of course, he could have made it all up, but I sort of doubt it. International also made the 232 and 258 inline six engines for AMC. AMC always sublet production of their main subassemblies to other manufacturers. The last all-AMC engine was actually the 352 V8 that was also used in the 55-57 Packard and the Studebaker Golden Hawk in 1956. I had a 56 Nash Ambassador Super with one of those engines.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!