The deck height of our stock 1965 200 is 0.031 inches (measured) and our OZ head combustion chamber volume after milling is 54 cc (measured), the cyl are 0.040 over. The pistons are stock and have a 7.3 cc (measured) dish. Thus accoriding to the For I-6 Performance Handbook the resultant static compression ratio with a Fel-Pro composite head gasket (0.055 inch compressed thickness) is 8.2.
Going to a zero deck height would make the deck clearance 0.055 and a compresion ratio of 8.8.
We would like to decrease the deck clearance from its present 0.086 to 0.040 to improve the "quish" (sp?) and move the compression up to 9.1.
This would require decking the block0.046 inches resulting in a deck heigh 0.015 inches BELOW zero.
At present the cam and rockers are stock. To compliment our Performance headers from Mike and Holley 8007 (390 flow) we are thinking about going to 1.6 rockers and/or 272 high lift cam. According the the Performance Handbook valve clearance should be ok even with this negative 0.15 decking.
THE QUESTION: Is it ok to deck below zero. If so, what are the limits.
Thanks, Dave
Going to a zero deck height would make the deck clearance 0.055 and a compresion ratio of 8.8.
We would like to decrease the deck clearance from its present 0.086 to 0.040 to improve the "quish" (sp?) and move the compression up to 9.1.
This would require decking the block0.046 inches resulting in a deck heigh 0.015 inches BELOW zero.
At present the cam and rockers are stock. To compliment our Performance headers from Mike and Holley 8007 (390 flow) we are thinking about going to 1.6 rockers and/or 272 high lift cam. According the the Performance Handbook valve clearance should be ok even with this negative 0.15 decking.
THE QUESTION: Is it ok to deck below zero. If so, what are the limits.
Thanks, Dave