The Ford Barn - View Single Post

rotorwrench · 09-10-2021, 11:06 AM

A lot of DIY guys are using converted GM distributors (early type) so they can have both mechanical spark advance and vacuum load control. I'm not sure if the 390 CFM Holley 4V carb that is recommended for flathead use has a port for load control but it might. The vacuum cans for the GM distributor can be purchased with the adjustable orifice inside so they can be tuned to work with a direct intake manifold pressure connection. This gives both performance and economy for street use. A person can use one of the old Mallory designs with centrifugal advance only but there is a loss of economy with these types. If the timing isn't right, the old flatheads tend to run warmer than I would care for in the heat of the summer months

The aluminum heads really have that old timey look but believe it or not, a person can get just as good or better performance with a set of EAB cylinder heads. For higher than stock compression, the cast iron heads like the 8BA and EAB can be milled but a person needs to insure that both are milled to the same dimension and that there is no less than .050" piston crown to chamber clearance when installed. Ford had the chamber design down pretty good. Most of the aftermarket designs aren't quite the same and many were designed for deck reliefs which have sort of fallen out of favor over the years.

09-10-2021, 11:06 AM	#23
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 18,012	Re: 1951 8BA Flathead A lot of DIY guys are using converted GM distributors (early type) so they can have both mechanical spark advance and vacuum load control. I'm not sure if the 390 CFM Holley 4V carb that is recommended for flathead use has a port for load control but it might. The vacuum cans for the GM distributor can be purchased with the adjustable orifice inside so they can be tuned to work with a direct intake manifold pressure connection. This gives both performance and economy for street use. A person can use one of the old Mallory designs with centrifugal advance only but there is a loss of economy with these types. If the timing isn't right, the old flatheads tend to run warmer than I would care for in the heat of the summer months The aluminum heads really have that old timey look but believe it or not, a person can get just as good or better performance with a set of EAB cylinder heads. For higher than stock compression, the cast iron heads like the 8BA and EAB can be milled but a person needs to insure that both are milled to the same dimension and that there is no less than .050" piston crown to chamber clearance when installed. Ford had the chamber design down pretty good. Most of the aftermarket designs aren't quite the same and many were designed for deck reliefs which have sort of fallen out of favor over the years.