Ross,
     For what it's worth I can't find either of those numbers in the 
parts books I've got, although they don't list the rare 8 port mk1 head, 
and might not include all the US variations.
However, I had a look at the pictures of the 8 port head in the Robson 
'Spitfire and GT6' book, (page 54) and that only shows only 4 studs on 
the carb side of the head, instead of 6 as on a normal 1147 engine. 
Presumably there are still 5 on the spark plug side making it a 9 stud 
head.
>..........was advised by several
>subscribers (thank you to all of you BTW), that "no" it is not
>because it has 11 bolts and the Mk. I and Mk II motors have 10
>bolts,
I think you might be getting mixed up here, the mk1&2 head has 11, the 
mk3 (1300) has 10.
Sorry to be the bringer of bad news but if it has 10 stud holes (5 each 
side) then it probably is a 1300 or maybe even a 1500 head.
Keith Bennett                                Keith.Bennett@bbc.co.uk
                           ___    ___
                           |HH\__/ ||
                           |HHHH|||||
        S T A N D A R D    |HHHH|||||      T R I U M P H  
                         __|HHHH|||||___
                        |   \__H|__/ HHH
                         \______HHHHHHH/
               
 |