In Reply to: Cast Iron Front Mount Distributors???? posted by Farmer Dan on October 21, 2018 at 17:52:25:
Here's how I perceive the MPC's and parts. First, I have two OEM 9N12131 in cast raised character bases with the circled (2). They both have the metal/4-hole vent & drain caps on them. The 2 is, in my opinion, a casting/mold number. It wouldn't be a part revision number. Revisions would carry a letter suffix code. A 'B' suffix indicates there was an earlier 'A' version. A part would obtain the 'A' suffix only when a later version was released to distinguish them apart. I think that any base without the FORD p/n is an aftermarket type, but could be wrong. Suppliers not licensed by FORD could not legally use the Ford part number on their parts. FORD was meticulous about having their logo and part numbers on most of their parts. However, the May, 1950 MPC lists the new 8N-12130 -base, angle drive part. The base casting basic p/n changed from 12131 to 12130 because it was now the angle drive unit. Why? the prefix "8N" would indicate it was a different part altogether. A recent OEM distributor spotted on ebay has the cast raised casting number and a circled (3), but no vent and drain plugs, only solid cast bosses. An original drawing of the cast base part 9N-12131 should indeed have the material spec on it, all revisions noted on it and/or the EI box. Early 9N parts were being changed often and some fell thru the parts books cracks. The 6-Loop Rims are a prime example. MPC's usually only list part assembly numbers, and not many casting part numbers. All of my MPC's, and I have hard copies of them all, only show the distributor assembly as p/n 9N-12000 with no suffix. That doesn't mean the base material spec isn't recognized, it only would be shown on the casting drawing. The basic distributor assembly and construction didn't change until the angle mount unit, a completely different animal, and thus a new part number, 8N-12127. I have never heard of a steel base front mount distributor. FWIW, the early 9N governors were cast iron, changed to aluminum housings, I think after the war, or perhaps earlier maybe '43 after the war board lifted restrictions. Drawings hold a wealth of information, but many early ones don't exist. I'm just spitballin' here, but I think when a part became obsolete, often times the original drawing was archived deep six, or destroyed altogether. Randy can probably answer this better.