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Good day all,

I'm wondering if anyone knows about how much valve-to-head clearance there is on a 327 straight 8. I had .008 removed off of the head because of warpage. The old head gasket measured .050, and the new gasket measures .072 before crush. I used clay in the combustion chamber and re-installed the head without the gasket and rolled the motor over by hand just to see what my clearance was. There wasn't any. The exhaust valves bottomed out on the head. I'm going to try to install the old gasket and use the clay method to try to measure clearance. I don't know how much, or if at all, the head has been decked before. Any suggestions or advice would be greatly appreciated. Ramon

As you suspect, ui would appear that your head has been shaved before, and more agressively. I do the same thing with clay but do it with the old (compressed) head gasket installed, and then check for remaining thickness of clay over the high edge of the valve. If it rocks even with the old gasket or the clay shows no clearance, there aren't many attractive alternatives other than shopping for another head, or trying two headgaskets which sometimes works fine, but generally isn't a long-standing solution.

A friend with the same problem after a shop foolishly shaved his head 0.060" had a special extra-thick solid copper gasket made by one of the firms that specialize in such work, but it only held up for a few miles.

I don't know what the 327 valves look like. Probably flat across the top. Make sure the valves are not crowned if they are supposed to be flat. Maybe someone found a substitue valve. Also check to see if hardened seats were installed at one time. Maybe the valve head is just setting to high for some reason.
In which case a new head mite not do any good.

It's a crap shoot.

I've said it before and i'll say it agian. All of this head milling that goes on is 90% nonsense and does not need to be done in 90% of the cases.

All of this head milling that goes on is 90% nonsense and does not need to be done in 90% of the cases.

Agreed! I don't recall ever seeing a recommendation on what degree of head warpage was allowable, but the longer the head the more the tolerance for it. I've installed plenty of heads on Packards that had 0.010 or 0.020 warpage and not had problems.

If you think you might have to mill the head, first cc the combustion chambers and the ends and center to see if it's been milled before. A little creative math with the volumes and you can even estimate how much (if any) it's been milled previously. If evidence doesn't prove it needs to be milled or surfaced, DON'T DO IT.

are u sure the valves are closing all the way?????

The measurement u really need is the measurement from the GASKET SURFACE of the head to the point in the combustion chamber directly in line with the valve.

Compare that to some other known good head measurement.

U will need to know that measurement for any potential replacement head that is sought for purchase . Otherwise the replacement head mite have the same problem as what is experienced now.

These are FLAT HEAD engines!!! Which means that the head is ez to R&R. If there is no CONSPICOUS evidence for milling then don't mill it! If there is CONSPICUOUS evidence then most likely the head is scrap to begin with and all of the milling in the world won't fix anything.

A head is EZ to R&R. Put the head on!!! If it leaks or causes problems then take other action. Maybe milling in some cases.
It's not like fitting bearings or pistons which is critical THE FIRST TIME.


THE CONCEPT HERE is to preserve parts that are fully serviceable insteads of constantly depleteing the supply by gimmick sales and service "policy" and other urban legends.

I'm surprised a free flu shot isn't offered along with all of this unconditional head milling hokus pokus.