The following information is subject to conformation. Now, having got the disclaimer out of the way, this is what I understand. The number cast into parts is the part number for the unfinished casting. Once the head has been machined for valve guides, surface ground etc, it takes on the finished item part number. Therefore you won't find the cast number in a parts book. If your cylinder head has close pitched fins then it will be from a T100 or Trophy, otherwise it would be from a T110 or an early Bonnie. I don't think the 6T ever came out with an alloy head. Not a definitive answer I know but I hope it helps a little.
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Usually folks don't pay much mind to what part number head they need unless it's a '59 Bonnie, but just what type of head, iron vs. alloy, single vs twin carb. So, my question concerns that, whether you have a single or twin carb head. If so, Identifying characteristics are; Single carb head alloy no stiffening rib between fins; three types for 650. '56 has a larger combustion chamber and not very many exist because they cracked immediately. From 57 same config except more meat around head bolt holes. (These are called the Delta heads and the name was used to describe both single and twin carb heads by some folks. Traditionally it refers to the accessory head that allowed twin carbs to be fitted to both the 500's and 650's although they differ in construction.) Then in late '61 a stiffening rib was added to both single and twin carb heads to reduce resonance. Good luck finding any of these heads without cracks at several of the head bolt holes. The 6T got the alloy head in 1961. '59 Bonnie head is identified by the existence of vestigal bosses for the single carb manifold not removed from the tooling. They were removed later in '59 so some genuine '59's may have the head without these bosses. And that is all I know. Bill
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As you know this is a single carb head. I have a few too. Check the opposite valve guide well for a cast two digit number with a circle around it. This will narrow down the year of manufacture. Most time in my experience the casting number such as E3548 is cast into the exhaust valve guide well....so look in the intake side.
Originally Posted By: Triton1974
Anyone know what year & model would have been fitted with an 8 stud alloy head stamped E3548? I have had a look through the parts books I have access to but no luck.