The Stovebolt Site Forums The Parking Lot Big Bolts huge GMC engine anyone?

I've been told the 637 cube V-8 is an IHC engine.And Mack offered a 707 6 cylinder gas engine,it it the same one GMC had?
6 cylinder gas engines were as large as 1000 cubic inches built by manufacturers like Continential before Diesels took over in the 50's