Hello, I have 100" engine with heads for dual plug application (4 x 12mm plugs). Last year I had mounted two spark plugs for each cylinder but it was hard to start engine (compression). So this year I decided to mount compression release valves instead two spark plugs. I have 10 mm Compression release valves and 12 mm to 10 mm Compression release Adaptors. Please let me know what tightening torques should I apply for adaptor and than valve?