Has my head ever been milled?

[64.5_pony]

Can anyone tell me how I can tell if my head has ever been milled? Is there a measurement someone knows about? I have a '64 Mustang with the original 170 engine and head and my head gasket needs to be replaced. The motor was rebuilt before I bought the car, but I don't know how to tell if the head has been milled and if so, how much.

Thanks,

Mark

 

[Explorer]

I'm by no means an expert, but I would say the only way to tell would be to cc the chambers and compare to stock spec's for that engine.

 

[CZLN6]

Howdy back Mark:

The first clue would be if the original steel shim head gasket has been replaced with a newer composite type. THe next step would be to measure the volume of several combustion chambers. A typical C3xx and early C4xx castings chamber volumes have ranged from 48 ccs to 53 ccs, so final results will still be an estimate. If your chambers come out in the range of 48 - 53 ccs, I'd consider the head original. A clean-up cut of .010" would reduce the chambers volume by aproximately 2 ccs.

IF your head is a late C4xx it will have 1.649" intake valves and 1.38" exhaust valves. If this is the case, the chamber volumes will be closer to 52 ccs, if they are stock. Check your heads casting code with special attention to the suffix.

To measure chamber volume, I believe there are several good posts available. Do a search. Measuring the chambers on your head will be the only way to accurately determine the chamber volumes.

Adios, David

 

[fordconvert]

After CC'ing the head dont forget to do the same to the bottom end. There are some odd combos possible over the years. Someone put strange pistons in mine that sit fairly low and shaved the head down a bunch to maintain usable compression. A stock head would have given me 6:1. These engines have been around a long time so anything is possible. Its best to measure to be sure you are going to get what you want.

 

[jamyers]

I'm thinking that the only good point to measure from would be from the rocker pedestal base to the block mating surface. Anybody know what that distance would be on an untouched head?