Pictured below are a series of pics of a Brumfield 5.9 compression ratio 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.
When selecting a cylinder head gasket, it is important that the gasket provide clearance to the valves, fit the combustion chamber opening properly, and not hang into or expose the gasket to the combustion gases when installed.
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 intended for use with a Model A Ford cylinder head on 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 or readily available.
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.
Larry Brumfield only recommends the currently available Fel-Pro 7013 R3 head gasket for use with his heads.
The newer Fel-Pro 7013 R3 gaskets use a modern metal reinforced graphite 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 block together with a stock Model B head (marked C).
It can be seen 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 Model B head gasket is that 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 Model B-6051 composition cylinder head gasket with steel fire rings on the Brumfield head. These gaskets were supplied to Ford by the Detroit Gasket Company, and are still fairly easy to find NOS in Ford wrappers at swap meets.
This gasket was originally intended for use with the stock Model B Ford cylinder head and Model B engine block. When properly installed, they seal very well to a stock Model B head, and are very difficult to remove because the asbestos material adheres itself to the machined iron castings very well.
The B-6051, or any other Model B gasket, is not recommended for use with the Brumfield 5.9 Model A head.
The gasket combustion chamber opening around the valves is designed to fit the Model B head combustion chamber outline shape, not the different Model A Brumfield chamber shape. The edge of the Model B gasket will hang into the Model A Brumfield combustion area and can burn.
Additionally, the extra gasket 'steam' holes are located very close to the fire rings and can be difficult to seal for water if the Brumfield head is being used on a Model B block.
These considerations advise against the use of a Model B gasket with a Brumfield head, on either a Model A or B block.