How do I measure my high head before I have it milled? I want to bring the compression up a bit but I don't want to go too far.
Check this out,
I have heard that you want to do at least .125 any less and you are just pretending. I have not done this myself so my advice is worth exactly what you paid for it.
Ken,the very small amount of increase you will get probably won't even be noticeable. The primary reason for milling is to achieve a good surface for gasket seal.
I milled one .125 a few years ago and within a year it cracked.
I couldn't notice any difference in power.
My 27 coupe is bored 0.060 over and the head was milled .060. The car will fly down the road.
Milling a high head is a waste of time. Milling a low head will give a noticeable change but may be more susceptible to cracking. If you want dependable performance gain spring for an aftermarket head offered by the T suppliers.
I do not believe you would find an unmilled head on a Montana 500 car.
Each head is an individual and may have been milled before. The made in Canada heads seem a bit thicker cast, FWIW.
I've had low heads milled .125" and used them with pop-up pistons with good results. I can't tell the difference between that setup and a Z head, except it all looks stock from the outside.
Use a few balls of modeling clay on the tops of the pistons, with the head in place. Turn the crank around a time or two, then remove the head and measure the thickness of the clay at various points. That will tell you how much clearance you have before milling. I'm told that .030" is the least clearance you want after milling, but mine didn't get that close. Some heads and blocks have been milled in the past, so you need to determine the clearance on your particular engine before milling it more. BTW, I suggest having the block milled a few thou before you begin the head measuring process, just to be sure the block is flat.
I believe that the cost will usually vary depending on where you live.
Big cities vs small towns.
Califunny vs Nebraska.
I routinely take .125 off of high heads using my Storm Vulcan headmaster. I haven't gone much past .150 as some heads heads start to get weaker or even fail past that.
I think from about 1914 up all Model T pistons were pop ups (not sure if the earlier flat top pistons came up out of the block), I am guessing you mean domed high compression. Will the domed high compression pistons work with a low head?
Never mind about if they will work, read the whole thing. DUH!
The new(ish) CC rules allow a Montana 500 high head to be milled about .080". Low heads typically can only be cleaned up before they will be too small for the Montana 500. I've never had too much trouble in regard to longevity with a head that is milled .100" or less. .125" will sometimes work pretty good, if it is a thick head. Some heads will take up to .200", but they are few and far between.