head bolt lengths

[Brandis]

I bought a set of new head bolts for my 47' A7 from SRM in the UK.  They seemed to know what they were talking about.   What I got was a set for  A7 and A10  and they don't fit.   And there's one too many.
3 different lengths.  The long and medium are too long and the short are too short.   All the ones available online look to be the same length distribution.   
I need 6 of one length and a slightly shorter one for the angled bolt.

[BSA_54A10]

The Stainless fasteners BSA ?Triump parts list ( search the forum ) has the bolts listed by part numbers
Look your up because the table has the thread form and lengths of each one of them
Then go to a specialist fastener shop & order them by thread form & length .

[Rex]

That seems rather optimistic, given that BSCy and BSF went out of common useage 60 years ago. Then you have the added complications of bolt specs, ie, length of bolt shoulder, material etc.
Odd that SRM can't get something so basic right though.

[JulianS]

The 1947 parts book gives the lengths;

7 x part 67 72 = 2 1/4 long under head x 3/8 inch diameter.

2 x part 67 71 = 1 3/4 long x 3/8 diameter studs at the rear.

Use high tensile with rolled thread.

Perhaps you could shorten some of the later bolts you have.