The Ford Barn

tubman · 06-28-2016, 05:20 PM

Today I pulled the stock heads off of the used '51 Mercury engine I am getting ready to put in my '51 Ford club coupe. First of all more good news; barely detectable ridge, no odd colors, clean water passages, etc. I then proceeded to check the dimensions on my Edmunds heads. We did the drivers side first. and got a consistent .150 over the valves. Clearance over the pistons was (front to back) .065, .055, .055, and .055. So far, so good. The passenger side came in at.170 over the valves. Clearance over the pistons (front to back) was .068. .070, .080, and .072. These were used heads I picked up locally and seemed to be in excellent shape in every way; no broken fins, good tapped holes (plugs, water outlets, etc.), and they seemed to be dead flat when checked with a good machinists straightedge.

I have to believe that some time in the past, the drivers head was milled .015-.020 to correct some minor problem. My plan at this time is to have .015 taken off the passengers side head to even things up. How does this sound to you knowledgeable flatheaders out there? I want to run the Edmunds heads as the spark plug placement will allow me to run extended tip plugs, which I believe that will help efficiency. This engine is being built for crisp running and economy first, with getting some extra power out of it as well. I will be running a converted vacuum over mechanical SBC distributor and a small base 2GC on a bored out aluminum Merc manifold (to start out; I have a couple of vintage 4BBL setups to try later if I'm not satisfied with the 2GC.

06-28-2016, 05:20 PM	#1
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,395	Combustion chamber "squish" question Today I pulled the stock heads off of the used '51 Mercury engine I am getting ready to put in my '51 Ford club coupe. First of all more good news; barely detectable ridge, no odd colors, clean water passages, etc. I then proceeded to check the dimensions on my Edmunds heads. We did the drivers side first. and got a consistent .150 over the valves. Clearance over the pistons was (front to back) .065, .055, .055, and .055. So far, so good. The passenger side came in at.170 over the valves. Clearance over the pistons (front to back) was .068. .070, .080, and .072. These were used heads I picked up locally and seemed to be in excellent shape in every way; no broken fins, good tapped holes (plugs, water outlets, etc.), and they seemed to be dead flat when checked with a good machinists straightedge. I have to believe that some time in the past, the drivers head was milled .015-.020 to correct some minor problem. My plan at this time is to have .015 taken off the passengers side head to even things up. How does this sound to you knowledgeable flatheaders out there? I want to run the Edmunds heads as the spark plug placement will allow me to run extended tip plugs, which I believe that will help efficiency. This engine is being built for crisp running and economy first, with getting some extra power out of it as well. I will be running a converted vacuum over mechanical SBC distributor and a small base 2GC on a bored out aluminum Merc manifold (to start out; I have a couple of vintage 4BBL setups to try later if I'm not satisfied with the 2GC. Last edited by tubman; 06-28-2016 at 07:15 PM.