Allis Chalmers Model B Mounting an original manifold cover plate (information plate) on a reproduction manifold

The new manifold castings that are currently available for the B do not have the large flat area and tapped holes necessary to mount the original manifold cover plate. This manifold cover plate is AC part number 207487 that shows up in the early parts manuals or part number 208009 that shows up in the last reproduction manuals that cover all Bs and Cs. I don't know what the difference is between these two numbers. I would refer to the plate as an "information plate" since it has some selected tractor information engraved on it. It is an aluminum plate. Here's what the plate looks like that was originally on my '42 B:

In order to mount this plate in the original location on a replacement manifold, I modified the manifold to add two tapped bosses as shown here:

The bosses are made from 5/8" diameter round steel bar stock that has been drilled and tapped down the centerline with a 1/4-20UNC thread. The bosses are each about 1/2" long (high) with the one on the left slightly less than that to accommodate an existing small raised area on the manifold. The top surfaces of the two bosses are such as to allow the plate to sit level on the manifold. Using the plate as a template, two holes (#7 drill) are drilled through the manifold and tapped for 1/4-20UNC threads. Short lengths of 1/4-20  threaded steel stock are used as connecting studs to attach the bosses to the manifold. Both bosses and connecting studs are set in a base of 2000 degF manifold cement to seal everything up. The replacement manifold had two tapped holes for mounting the later, thru-the-hood style exhaust muffler. Since I was using an original style, underhood muffler, I did not need the lower of those two holes so I plugged it with a stainless steel hex head bolt cut to a suitable length. The plate is then mounted to the bosses using two round head, stainless steel 1/4-20 machine screws and lockwashers. Here's what it looks like with the plate mounted: And here's what it looks like after mounting on the tractor:

I used Eastwood's High Temperature Factory Gray manifold paint on the new replacement manifold but I am not satisfied with the results. After two years of being outside it has rusted completely through the coating as you can see. The rusting began a couple of months after being outside so this is not a product that one can just apply, forget about and still have a like-new appearance retained. If anyone would like to make a reproduction plate for their tractor, I have made up a detailed, dimensioned drawing of the one on my '42B. It is available here in Adobe .pdf format. Rod (NH) January 2006 Home