[BRENT in 10-uh-C]

To muddy up the waters a bit, does anyone remember the diesel fuel conversion for a Model-A engine? As I recall, it was like 16:1 CR on cast bearings. It sure wasn't the compression ratio that was the downfall.

And, FWIW, several of the mid-50s build OHV conversions were 10:1 weren't they Jim? I had a single stock Gemsa that was at least that. As stated above, it is Volumetric Efficiency that is/was the issue with high compression flat heads. F-heads and OHV have no issue with higher compression.