Reply to ""L" engine"

DeTom

that change alone will be worth about 2 to 7 bhp. I don't think its worth it. However the compression ratio increase is often felt in the seat of the pants as a boost in low rpm response, and eveybody likes that.

"IF" you were changing the camshaft to a hotter grind, and the camshaft manufacturer called for a motor with a compression ratio in the 9.5:1 range, then yes bolting on the cc heads would be called for.

Otherwise, what you need to do with your motor is zero deck the block, install fordged flat tops pistons. This gets you about 10.0:1 compression ratio. If the compression ratio needs to be adjusted lower for the cam & fuel you've selected, then dishes should be machined in the tops of the pistons that mimick the shape of the combustion chamber in the cylinder head (i.e. we're talking custom pistons).

All of this work is aimed at maximizing squish, which is the real power maker, more so than just a compression increase. Instead of 2 to 7 bhp, the gain realized by this work will be on the order of 30 bhp or more, depending upon the state of tune of your motor.

cowboy from hell