I found a set of 81T Aluminum heads. So far I can only find info the cast iron versions with about 83-85cc chambers on trucks from 1938-1942. Are these also truck heads? Are they for a special application? What is the combustion chamber size on the aluminum version? Thanks, Roger
I don't think there were aluminum 81T's listed...truck heads were almost always iron. There are both USA and Canadian 81A's, Canadian 91's in aluminum, none of them very easy to find, and the super-rare iron high compression 81AS "Denver"... I have some very early Canadian and US bulletins on these, and can research further. Whatever the books turn out to say, you've got something unusual. What CC's do you have? You can do a reasonable rough check by just leveling one and filling up a chamber with something like a CC'd medical cup.
I don't have them in my possession yet so I can't check the chambers. From the pictures of the heads, they look like they are aluminum and not cast iron. I am trying to get in contact with the owner to verify this or not. Roger
These heads have been confirmed to be aluminum since they only weigh 10 lbs each, but I have no way to find out what the combustion chamber size is. Roger
Forgot about these...will try to remember to dig into the books. I'm pretty sure these things don't exist even in the period catalogs and superceded early bulletins I have, and I've never seen any others, so this is something really unusual. If you gettem and use them on a postwar block, clearance at top edge of valves needs to be checked as some require very minor clearncing for late valve angle.
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