Need combustion chamber volume's

[walt jones]

Can anyone tell me the volume in CCs of the combustion chamber In : 1. a stock Model A head, 2. a Snyder's 5.5:1 head, 3. a Snyder's 6:1 head ?
I have purchased an HC head and am trying to determine which head that I have.

Thanks

[walt jones]

Does anyone know this information or know where I can find it ?? TNX W

[Joe K]

Maybe call Snyders? They must have a way to tell their two different products apart?

Joe K

[160B]

Chime in on this thread there are already some volumes posted in the 3rd comment.

https://www.fordbarn.com/forum/showthread.php?t=98235

[bphillips]

A lot depends on how much your pistons hang out above the block, as well as the bore (oversize) of your block, but a combustion chamber volume of about 150cc's should get you close to 6:1.

[eystein]

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I would think that the answer to your question can be easily calculated.

With the stock model A having a bore and stroke of 3.875" X 4.125", you can calculate the volume that the piston displaces on its travel to be 48.65 cubic inches.

Now, with the stock head I think the compression ratio is 4.22 to 1.

Now, the 1 is the volume left in the head when the piston is at TDC and the 4.22-1 = 3.22 is the volume that the piston displaces.

Hence the volume of the chamber in the stock head equals 48.65 cu. in / 3.22 = 15.11 cu. in or 247.6cc

For the 5.5 to 1 head, the volume of the head chamber should be 10.81 cu. in or 177.2 cc

For the 6 to 1 head, the volume of the head chamber should be 9.729 cu. in or 159.4 cc

[ursus]

We may not actually be able to tell you what kind of head that you have as there have been easily a dozen or more manufacturers of high compression heads over the years. That said, there is a Ford reference to the stock head having something like 242 CC. I have a new Snyder 5.5/1 head that measures 168 CC and another old head of unknown provenance measuring 147cc, which I take to be around 6.2/1. One variable is the choice of head gasket, as some will compress more than others.

[bphillips]

I thought about posting the mathematical answer that Eystein posted, but took the lazy way out after going through the math. The only thing I would like to add to that post is that the head gasket volume (more than you might think), Valve head volume (enough to make a little difference), and the aforementioned piston/deck height volume must be considered. When they are taken into account, the 150 cc chamber comes very close to yielding a 6:1 ratio on the average rebuilt A engine.

[BRENT in 10-uh-C]

You don't need CC to distinguish the differences between those heads as all three have different shaped combustion chambers. Post a picture of what you have and we can likely tell you.

[Steve Wastler]

As Brent says, take the easy route and post a picture.....