Pictured below are a series of pics of a Brumfield 5.9 cylinder head for the Model A and B Ford.
A variety of cylinder head gaskets are shown positioned on the head. You can get an idea of the differences in the fit.
Above is a view of the combustion chamber outline and design of the Brumfield 5.9 compression ratio cylinder head.
Pictured above is the Brumfield 5.9 head with an old-production Fel-Pro 7013 R1 version head gasket. The 7013 R1 is the gasket for a Model A Ford cylinder head when used with a stock bore size engine block.
The bore opening in the R1 is 3-15/16 inches and is intended for standard cylinder bore sizes, up to about 0.060 oversize.
The Fel-Pro 7013 R1 uses an asbestos type filler and is no longer in production.
Pictured above is a direct comparison of a current available production Fel-Pro 7013 R3 version head gasket on top of an old unused R1 version gasket.
The newer Fel-Pro 7013 R3 gaskets use a modern aramid reinforced filler material. One reason Larry recommends the new R3 gasket is due to the higher strength and higher temperature tolerance of the newer filler material.
The bore opening on the R3 is 4-1/16 inches and is intended for cylinder bores from about 0.060 to 0.125 inch oversize.
As seen in the pic above, there is no measurable difference in the Fel-Pro 7013 R1 and R3 gasket profiles in the radiused corner areas around and between the valves. The main differences are in the bore opening diameters, and a very slight difference in the area between the valves and cylinder bores.
The pic above illustrates the fit of the Fel-Pro 7013 R3 cylinder head gasket on a 0.040 oversize cylinder block, showing the oversize fit to the block and the thin gasket material between cylinders.
Larry reports that the relatively larger bore opening of the Fel-Pro 7013 R3 compared to the R1 has not proven to be any problem for sealing or blow-out or burn-out between the siamesed cylinders, and that the R3 gives excellent service.
Shown above is the Fel-Pro 7014 composition head gasket on the Brumfield head. This gasket is intended for use on the 1932-34 Model B engine and stock Model B head (marked C).
You can see that this cylinder head gasket does not follow the Brumfield chamber opening as well in the valve area and exposes a little of the steel fire ring especially near the head stud.
Another reason to avoid this head gasket is because it has the extra 'steam' holes near the center stud. The Fel-Pro 7014 can be a very difficult gasket to seal for water in my past experience, and I would avoid trying to use it again.
The gasket shown above is an NOS Ford script B-6051 composition cylinder head gasket with steel fire rings. These gaskets were supplied to Ford by Detroit Gasket Company, and are still fairly easy to find NOS in Ford wrappers at swap meets.
This gasket was intended for use with stock Model B Ford cylinder heads and Model B engine blocks. When properly installed, they seal very well to a stock Model B head, and are very difficult to remove since the asbestos material seem to glue itself to the machined iron castings.
As a side note, this NOS B-6051 Ford head gasket is what I currently have on my stock Model B, with original Model B head and Model B engine block. I took my rattiest NOS Ford head gasket and covered it with copper spray coat and installed it.
I was thinking that if it wouldn't seal, I would just throw it away and try the next rattiest one at hand until I got one to seal. It leaked a little so I took it off and shot it again with copper spray coat and re-installed it. I was finally able to get it to seal, and it has been okay since then.