Since I’m an AMC fan, I feel like I should tell you this. The 232 and 258 engines got a bellhousing pattern change for 1972, making it the same as the AMC V-8. I found this out the hard way. The Buick 225 V-6 also had a bellhousing change in 1964 to the standard BOP pattern. This guy I used to know had a real early-’60s Buick with the 225 V-6 in it. GM had this engine on paper in the late ’50s. I had worked in a car repair shop for 18 years and have seen some weird Jeeps. One guy allegedly ordered a brand-new Jeep pickup with a 304 IHC in it! Another guy allegedly ordered a Jeep pickup with a Pontiac 350 in it! I did work on both of them.
The very first time I saw the words “All-Wheel Drive” was on a Jeep pickup back in the ’60s. Why didn’t Jeep copyright that term?
There may have been some sort of mix-up or misunderstanding with the owners of those Jeep trucks. The International Harvester 304ci V-8 was never available in the Jeep pickup. However, the AMC 304ci V-8 debuted in ’71-model Jeep pickup trucks, among other Jeep models. Many people mistakenly think the AMC and IH 304 V-8s are the same engine, which they are not. The only thing they have in common is displacement. As for the 350ci engine, that would be a Buick V-8. It was named the Dauntless V-8 under the Jeep brand. The Buick-sourced engine came online in the Jeep trucks in 1968.
Now, it is possible that someone may have swapped an International Harvester 304 and a Pontiac 350 under the hoods of the trucks you worked on, although it isn’t very likely. Neither of these engines have been popular swaps for Jeeps in the past nor present.