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 Matt
My close friend who has driven Model "A"s since he was 14 tells me that he won't go over 6:1 on his. Keeps the lower end together longer, at least with stock crank & poured bearings.
Yes this is what I’m hearing if you are still running Babbitt. (Which I am)Thank you for the info. Just trying to get to a comfortable 60mph. And have enough pep to keep up with normal traffic.
few options The old school way, 2 head gaskets, I have seen it work but I would not trust it. Have Dan flycut the head for the pistons or any machine shop can do it too. I put my pistons in the lathe and removed some of the top material to get mine just below deck height.
.040 to .045 should work fine as long as you clay it and do not go under .040. One of my engines won top eliminator 4 banger at the Antique Nationals several years ago and it was running .030 on 100% nitro. I have used Dan Price heads on several race engines at 12 to 1. He can tell you how to modify them for that if need be. I would not worry about the babbit for a street engine. They used to run babbit in 500 mile races and turning 6000 rpm.
The friends I know with them have all added overdrives behind the transmissions. A little expensive but all of them are happy. For most of the trips and freeway drives they go on the roadways are obviously totally different than the 30's and maintaining 60-65 has been really ez for them. A friend with a 32 roadster with a later flathead built in the 40's style is currently adding one to his car for the same reason, some freeway driving. Good luck
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