Anybody running the '68 4 speed 340 cam?

RustyRatRod said
You're confusing compression ratio with cylinder pressure. The two are totally different. Cylinder pressure is what the engine physically produces in a give configuration, fully assembled. Compression ratio is the comparison of the cylinder volume from bottom dead center to top dead center. You've already said your cylinder pressure on one measured cylinder was 150. That's pretty low for that camshaft. I can't beat it into your head enough how important this is IF you want to tune this engine. But, like I said, if you're happy with it, don't worry about it.

I am well aware of the differences. Ken used the terminology calculated compression which is why I was referring to it. He knows the valve timing.

I've never seen any guidelines about what tuning parameter you would change based on cylinder pressure. Got any? All my engines have run with about 15-20 degrees initial and 34-36 all in. Most every recommendation you will find falls between 34-36 (street engines anyway). Initial timing isn't critical and can vary in that you should be more concerned about total timing.

RustyRatRod said
The problem is, there are so FEW original 340 4 speed engines out there. You are going to be VERY lucky if someone comes forward with the information you need. I sure wish you luck, though.

Thanks. Its not that important though. I was just curious. Lots of repro cams like this were sold so you think someone here would be running one.