Once I get the new oversize valves fitted (properly) to the problem head, it's going to be interesting to do a CC test on it and calculate the static compression ratio when it's combined with a "261" engine that's actually going to approach 300 cubic inches. The "more is better" approach to compression is sort of a myth, since a lot of people don't understand WHY compression is increased on a high performance engine. When a radical camshaft is installed into an engine, it gets that extra power (only at high speed) by keeping the valves open longer- - - - -opening earlier, and closing later. In the case of the intake valve, that means that a good portion of the compression stroke happens before the valve closes. It's impossible to build up compression pressure in a cylinder with a valve open- - -even slightly. So- - - -if you want to get the compression pressure back up to where it was on a stock engine- - - -you've got to squeeze what's left of the cylinder harder. That requires a dome on the piston, and/or a smaller combustion chamber- - - - -JUST TO GET BACK TO SQUARE ONE!
Increasing the compression ratio without installing a radical cam approaches a situation where spark plugs aren't required- - - -better known as a Diesel engine! Most gasoline engines aren't built to survive that kind of abuse!
Jerry
