Safe "Squish band" for a model a head

M

Matts30coupe

Member
Looking to buy a performance head for my model A build. Motor has been freshly rebuilt yrs ago. It was an old guys spare. I will be taking it down to check it all out before building it back up.

Question is that I am looking at getting a performance head for it.

I would like to shoot for a 7:1 compression ratio. I like Dan Prince aluminum Thomas repos. Thing is, that there is no flycuts... My pistons come above deck .010" now. Gasket looks to be cold .055". (Maybe add .005" for compression of head gasket.) So, I am looking at .045"-.040" of a squish band. I have heard for a model A driver you want your "squish" to be around .060"+- maybe .005"?

So I am wondering my options. I can pull the pistons out and cut some off the top in the lathe, or have a machine shop fly cut the new head. Wondering what people have done in the past. I am worried that my setup now is too tight, and want to avoid my pistons kissing the new head when the cylinder grows.

Anything will help, thank you!
Matt
 
Ideal quench (what you call squish band) is .040,so it appears you are good.The best 509c copper gasket is pretty thick as well.Measure 5 times fit once,be dead on in your factor,you can use a piece of modeling clay to squeeze and measure as a test.Its not expensive to have your head flycut to achieve the desired clearance and it doesn't lower the compression ratio measurably...maybe a few cc's. Be sure and use a waste metal with your aluminum head..I'm pulling my aluminum,got a cast iron one.

q1YSLBS.jpg
 
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Sacraficial anode. I had a threaded bung installed in radiator top. You can get threaded pencil anodes from boat supply, makes a really easy way to change them. I was able to get away with a Super Winfield with no fly cut. Test with clay balls or balls of aluminum foil. I did it without the gasket and with, as told to me by an old flathead racer. Do the test a couple times to be sure. i use the Best 509 graphite.
 
Thanks! I figured it was something to help will corrosion. Nosetime, do you remember your specs. Or distance from piston to head? How did it run?
Matt
 
I will look for the info. I took pics of my piston protrusion above the block and mic of my balls of foil. Give me a bit. PM for easier info
 
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