Engine ID help

I just picked up a 74 and I can't tell if its a 232 or 258 according to the 74 manual the engine build code should be an "A" for the 258 and a "E" for the 232 my code reads as follows 310G15 It very well may be that the engine was swapped out at some time. Any thoughts or idea's?

 

G indicates a 232 according to this site: http://www.geocities.com/cantwait_forviolence/cj_numbers.html

I would decode it as a 232 2bbl built on 10/15/73.

However, I don't think a 2bbl 232 was ever offered in a CJ. Maybe it's a car engine that's been transplanted? I know the FSM for 74 only shows 1bbl versions of both the 232 and 258 being available: http://warloch.com/74 Jeep Manual.htm
and the FSM specifies the A and E engine codes. My guess is it's an AMC car engine.

 

Thanks for that link, interesting, it has a one barrel on it but I'm sure that could have been changed at some point.

 

Likely. If they replaced the long block they probably kept whatever manifolds came on your original engine. Your VIN should tell you what engine you originally had. I'm guessing it came with a 232 1bbl and somewhere along the line someone replaced it.