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tubman · 03-20-2025, 04:37 PM

Since I prefer Edmunds heads, I am becoming an expert on used heads. The best thing you can do is to temporarily test fit the heads to an engine and check the clearances using aluminum foil balls and a used gasket. Amazingly, every set of used Edmunds heads I have checked (except the last set that I haven't gotten to yet), required additional milling to bring them into a nominal clearance of .045"-.050" over the piston heads. I check 8 or 9 places on the piston and each valve. Typically, I have needed to take .020"-.030" of the heads to get them close. Generally, this is enough to greatly reduce the pitting and corrosion around the water openings. They need a little attention with a die grinder after that to bring everything into spec.

Maybe I'm just lucky, but then again, I probably need it. I've gotten so I can see if a set of heads has been milled too much by judging the diameter of the circle round the combustion chamber.

03-20-2025, 04:37 PM	#2
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 11,629	Re: Used Aftermarket Aluminum heads. Since I prefer Edmunds heads, I am becoming an expert on used heads. The best thing you can do is to temporarily test fit the heads to an engine and check the clearances using aluminum foil balls and a used gasket. Amazingly, every set of used Edmunds heads I have checked (except the last set that I haven't gotten to yet), required additional milling to bring them into a nominal clearance of .045"-.050" over the piston heads. I check 8 or 9 places on the piston and each valve. Typically, I have needed to take .020"-.030" of the heads to get them close. Generally, this is enough to greatly reduce the pitting and corrosion around the water openings. They need a little attention with a die grinder after that to bring everything into spec. Maybe I'm just lucky, but then again, I probably need it. I've gotten so I can see if a set of heads has been milled too much by judging the diameter of the circle round the combustion chamber.