charliemccraney (6/28/2013)
Ted,
What do you call high compression? My machinist friend, Don doesn't call any street engine high compression.
On my end, 11.0:1 would be considered high compression depending upon the camshaft and if being normally aspirated. In other cases, anything that does not run satisfactorily on pump gas might be considered high compression and that could be engines with the static compression ratio as low as 9.0 or 9½:1. Fuel octane itself becomes a major player here. ‘High’ in this case is a subjective term.
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The Autolite 124’s would be on the cold side for a stock Y but would have been suitable in trucks where they were heavily loaded and run hard much of the time. That heavy duty truck usage with a Y might have been seen on a regular basis fifty years ago but not now. The 124’s still work well in boosted applications where combustion chamber pressures are artificially increased regardless of the advertised compression ratio. Many parts stores still carry that 124 number as a carryover from the FE truck stuff.