Before this topic gets lost,I thought I would bring it back to the front.
Randy has posted this:
The 9N-14301 ground strap was released in 5/39 and had some revisions in June, August and October that year. It was revised again in Feb and March of 1940, and then in Oct. '41. It was 5.0 to 5.5 long, center of .34 dia hole in flat end to center of battery post clamp (sized for positive post), and no sign of this being revised ever. It was a 2 gauge woven leaded strap. Ends to be soldered and coated all over with lead. Then entire assembly to be dipped into hot petroleum jelly .
Randy, is there any chance the last revision in 41 was to shorten the strap and reduce the hole dia.to .340?The .340 hole in the strap,would indicate to me that a 5/16 " bolt would be used to secure the strap to ground.The only 5/16" bolt that would even come close to working,would be to the gas tank,and I don't think Ford would be making a ground connection to a gas tank.According to the 41 parts book,the air cleaner to battery tray bolts and the tool box to battery tray bolts were 7/16" and will not go thru a .340 hole.It is still my opinion that the early 9n tractors used a 10-11" strap with a possible 1/2" hole.I'm hardheaded and a dummy,and may be as wrong as wrong can be,but there is just not any place to connect a 5.5" strap with a .340 attaching hole, on the aluminum dash tractors,that I can see.Is there anyone on this board with a 39-41 9n with the aluminum dash, that has a 5.5" strap?If so, how and where is the strap grounded without drilling a hole in something,which I don't think was supposed to be.All comments appreciated. don b

I believe after serial# 12500 it bolted to the rear hood to dash bolt which is 5/16".

Scott....do you know where the ground strap was connected on the 1939? don b

To the side of the battery tray with the 7/16" air cleaner bolt.

Scott....that's what I thought,but according to Randy,the hole in the strap is only .340.Maybe the hole got changed on one of those revisions?? What length would you say it was?A 5.5" strap won't reach that far. don b

Don,
I'm still with you on this one. The hole on the strap is just too big to attach to the hood, and there is no pre-drilled hole on the dash (like the 2N) to which to attach it. Regardless of the battery orientation, I can only see a longer strap being connected on either side of the battery tray, behind the air cleaner or toolbox.
Now I can see the negative cable was changed, from a shorty when the starter was dash mounted, to the much longer cable when it was transferred to below the battery. Just can't see them ever using a short positive ground strap.

don, to change a hole size down on this part would have made it not interchangable on the older application, and it would have been breaking the rules of part numbering. This should have caused a new part number. There were some instances where we know this rule was broken for some reason. I think this is all pointing to the shortage of engineering manpower during the war years and defense buildup (read Harold Brock's book); some documentation was missed at times, apparently. We really need to get into the archives and read the changes J7, numbers 97, 228, 268, & 310; and the K7, numbers -(3-15-40) and 246.
The hole size was what made either that end or the whole strap different from 48-14305, an automotive part. They are probably just talking (in the note) about the flat strip of brass wrapped around the woven strap at the end to punch the hole into.