A10 cam gear

[BritTwit]

I need some advise on a parts book mystery.  I removed the cam gear from my '60 A10 Spitfire and my '53 Super Flash.  The gears were stamped 67-338.  I also had another 5 67-338 on the shelf.  The 49-53 as well as the 1960 parts book shows 67-337.  My 1970 A65 parts book shows 67-338.  My price sheets from 1950 to 1965 show no supersession or consolidation of the two.  In checking on the web with a supplier, both photos appear indentical, down to the timing mark location.
I have no A65 parts in my shop, only A10.  Where did all of these 67-338 come from?

[KiwiGF]

I need some advise on a parts book mystery.  I removed the cam gear from my '60 A10 Spitfire and my '53 Super Flash.  The gears were stamped 67-338.  I also had another 5 67-338 on the shelf.  The 49-53 as well as the 1960 parts book shows 67-337.  My 1970 A65 parts book shows 67-338.  My price sheets from 1950 to 1965 show no supersession or consolidation of the two.  In checking on the web with a supplier, both photos appear indentical, down to the timing mark location.
I have no A65 parts in my shop, only A10.  Where did all of these 67-338 come from?

Could it be a casting number on the gear and not the part number? Typically the casting number is one or two digits different to the part number. I don’t recall seeing casting numbers on gears, just on things like foot rests or timing cases, but maybe they are on some gears.

There is also some variation on whether or not parts have casting numbers or not, depending, I think, on the company that bsa asked to make a particular batch.

[BritTwit]

Thanks for the input kiwgf. 

True, the casting number is one digit off from the part number, but these numbers are stamped on the face of the gear.  Normally I would assume the 67-0337 was consolidated with the 67-0338.  However, the price list shows separate numbers all the way up to 1967.