Good info from the boyz. May I add, You can tell whether an early Chevrolet or GMC starter is 6 volt or 139 ring gear teeth because the starter drive pulls out straight. The armature has straight splines. The 12 volt or 168 tooth ring gear starters have helical splines on the armature and will twist when pulled out.
Also the exposed end of the starter shaft on the
12V starter will be .470 while the 6V starter has a shaft diameter of closer to 5/8.
OK now Richard Bowman, "Checking connections" is fine but a voltage check/starter check is what should be done. You really need to be specific about what "no go" and "failed to work" means. If you want to jump to buying a new starter, that's OK with me but if you want to know what's wrong then state what it does when you stomp the foot. Noise? no noise? partial rotation of starter? Then we can do tests, with a meter, to see if starter system is getting juice and is grounded. As you know, there is a big cable from battery to starter. We don't know if you have a foot start BUT: The foot button pushes a lever down onto a plunger switch that pushes down and touches a big lug contact on the starter. After we hear what it does or does not do, we may suggest a new plunger switch or a new lug, both available. Don't know when "during the rebuild" was? Just rebuilt? Starter been OK for 500 miles? That's not a whole lot of starts.
If it was mine I would take off starter (very easy) and play with it on the bench using my battery charger as a power supply. Could be brushes. These starter motors are very robust and easy to repair most of the time. Had to change to Richard because your name is automatically censored. Isn't that special?
Jerry is the last guy to say slap on a starter before testing anything, but he realizes it's your money not his....or he has changed his M.O. without letting us know.(insert some kind of smiley face thing here)
Be advised the starters are not all that available. None at the places listed. Most will be rebuilt. Classic Parts of America is $160 plus shipping. 6V, 12V or 12V conversion ($170). All rebuilt and have a $125 core charge.
