Slant 6 questions
Definitely do the
Fuel line mod. Battery cable is a perfectly ordinary, plain, standard item -- buy by length. Much more interesting and informative than a VIN stamp on the engine is the engine stamping itself, which is below the № 1 (frontmost) spark plug.
Tune-up parts and technique suggestions in
this thread. Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted
here for free download. Your son needs the three books described in
this thread.