Ser III Compression Ratio

[Edscripps]

I would like to verify the compression ratio on my 74 series III, the engine number which begins with 904 indicates it's 7:1, but I was told the best way to confirm was to look on the cylinder head and the compression ratio is stamped on the side. Does anyone know where? I can't seem to find anything that looks like #:#.

Thanks,
-Ed

 

[wally.aussie]

7.1 verses 8.1

gday, the easiest way to tell is look behind carby at the head and if there is a raised section between the centre head bolts on the head it's an 8.1, sometimes stamped, the 8 looks like 2 zeros on top of each other. if no raised area 7.1. hope that helps, cheers