RE: Military GMC Engine
Well ;
I worked on a few of those back in the 60's , I know NGK still made the spark plugs a few years ago although I'd bin the entire waterproof & radio shilded ignition system my ownself as they're a PIA
IMO .
I'd guess it's a 302 C.I.D. but I dunno .
I wish I could see it as I have " Long Motor Envy " like most Bowtie owners....
Being a Jimmy , I'd just flush it and tune it , see how it runs then slap it on in and be happy .
_7_ main bearings , high nickle content cast iron , the list goes on........
-Nate