quote:Also I got a question about CJ spec clevelands. I had heard that along with dropping the compresion ratio a whole ton, they also retarded the cam by four degrees to pass smog tests. Wouldn't just taking the cam out and turning it back four degrees without doing nothing else make you engine livelier??
Maybe- depending on the combination of parts inside your engine. What Ford did in late '72 was to retard the camshaft 4 or so degrees by changing the silent-chain crank sprocket's keyway location. Changing cam advance only shifts the powerband up or down the rev-range; it normally doesn't increase it. All aftermarket roller cam chains recommended for 351Cs have multiple keyway slots for those who want to tune their engines. Decades ago, builders used the 4 degree advance key-slot to compensate for expected chain stretch after 500 miles, but nowadays with modern cams and better quality cam chains, 'some' extra advance is already built in by the cam grinder. So I don't advocate blindly cranking in more cam advance without first checking as to what the effect will be on power, or valve-to-piston clearances. Dyno-tuning an engine pays many dividends.