Mystery CL77 head

[tommy]

Many years ago I aquired 2 truck loads of CL77 parts/bikes.<br />I have just now started putting things together for the first bike, an &quot;orange&quot; '67, big wheel.<br /><br />I selected the best head for rebuild, but found something<br />very strange on it.<br /><br />On all the other heads, between the intakes,<br />there is a capital &quot;H&quot; stamped at the base, but on this head<br />there is a capital &quot;M&quot;. The &quot;M&quot; is vivid and was clearly cast<br />in when the head was created.<br /><br />I compared all the heads and found only minor differences,<br />such as fin arrangements.<br /><br />Does anybody know what this &quot;M&quot; is about?<br />I seriously doubt that anyone made an aftermarket head,<br />so this is very puzzling to me.<br /><br />tommy<br />

[kl]

i could be totally wrong but this is my theory.i have stripped quite a few 250/350k twins and they too show differing letters.in fact one head had slightly different shaped fins on front/fin on lower extreme of exhaust port machined away.i reckon they are revision marks or mould no.:marks.....kl