Question for the flathead experts. After installing the new camshaft in the 1937 21 stud, there is no valve clearance, with the factory "Made in Canada" aluminum heads. We have no idea if the heads have ever been milled or not and are reluctant to cut into the heads for more valve clearance, so would like to find an aftermarket head. Does anyone know of an available head for this engine, since it seems to be an oddball?
Brand new Eddie Meyer 21-stud heads are available from Don Orosco and last time I looked in a Reds Hedders catalog they listed a no-name finned aluminum 21-stud head. The only thing is that these heads are made for the '32-'36 configuration with the waterpumps on the front of the heads. Back in the old days Evans and Federal Mogul also made 21-stud performance heads.
For the bump.... All was fine until you added the new cam? Is this a performance cam? What flavor is it? If so, Sounds like you bought a new cam and not a reground. Back in the day most all Flathead Performance cams were reground Factory originals that Isky etc. pulled from scrap yard motors. In regrinding a factory cam, you loose .100 of the cams base circle which is fine if you add 'what most refer to' as "Chev Valves". The chev valve is .100 longer than stock and hence it works fine with a reground camshaft as the cams base circle has lost the same .100 that the new valve now adds. Back in the day, the factory Canadian service manuals (1939) recommend grinding the stems of the valves to get down to the required clearance. -Of course that was for stock rebuilds (with/without slight head shave) but is still plausible for other than stock builds or when installing high lift Non Reground Camshafts. Also, there are 2 different types of pistons used in 21 stud motors. Domed and Flat topped. The heads must match the pistons or you will encounter clearance problems, hence there are 2 different styles of Canadian aluminum and cast iron heads to match. I do not know what the aftermarket heads are made to run with, check your supplier before purchase. Re: bottom of this page, operation 6050D -Also, a guy should note that factory specs for torquing your Canadian aluminum heads is -Only- 40 ftlbs. Hope this is of some help. .
Thanks for the onfo everyone. Moe the cam is an Isky Max 1, and the valves were already cut down as you mention. Since posting this, I also found a picture and info about factory block off plates for the waterpumps, so the early heads with the pumps on the heads could be used for warranty purposes. I wonder how hard those would be to find? They would make it possible to run an early style aftermarket head, but they would then have to be compatible with the pistons that were for the original heads. The pistons are also the correct ones for the "Canadian" heads with the unique chamber configuration.
if your heads have .375" clearance at the valves, the max 1 should work, but that's about the limit. isky has an 88 cam that's a step up. it's considered a "full-race" cam and has a .320 lift (max 1 .364) but longer duration (264 vs. max 1's 249). hope that helps.
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