Compression Ratios

["elanrhys"]

Hi,
I'm trying to work out the compression ratio of my non-federal
Stromberg Head (H) Stamp.

I've CC's I've measured:
combustion chambers 37cc.
Piston Cut outs 2cc
Head gasket (84x1.2mm) 6.7cc

This gives me a total of 45.7, and given a swept volume of 389.34,
Gives me a compression ratio of 9.5:1. 45.7 / ( 45.7+ 369.3)

The combusion chamber ellipse aeverages out at 71mm, so theoretically
shaving 40 thou of the head= 4cc.

This gives a new total of 41.7, which works out to be 10:3 . This
corresponds to the big valve ratio.

So is the Miles Wilcons Twin cam book round saying the H stamp is
10:3 to 1?

Thanks
Rhys