I'm getting ready to order up a new 355 tomorrow:

Eagle ESP Forged 4340 crank and H-beam rods, Diamond ultra-lite dished pistons.

My cylinder heads have been milled .010", and I'm not sure what this has done to the combustion chamber size. Anyone happen to know this??

My main question is how much of a difference in power is a compression of 10.5 or 11.0 versus 11.5 or 12.0 going to make. I can't really match the compression ratio to the cam as I don't have a cam yet (going custom, need to get heads flowed), so I figured I'd shoot for something safe.

But, the questions burns, will moving it a point either way have an pronounced effect on power?

 

My car is 13:1. According to Dyno 2000 it makes 608hp at 6500 and 566tq at 5000 which is just about right for the times I run.

Dropping the compression down only lowers the numbers but not the peak rpms to:

12:1 - 589/553
11:1 - 568/538
10:1 - 543/520

So according to dyno 2000 my engine makes 20-25 more hp per point of compression. Running alcohol is nice but I'd like to be closer to the 14.5:1 range for compression.

Increasing the compression can be a step backwards if your octane is too low and the engine start detonating. Even with the electronic fuel management systems you can run pump gas with 12:1 compression but if the computer retards the timing too much to prevent detonation then you're just losing power.

 

http://web.camaross.com/forums/showt...hreadid=231595

http://web.camaross.com/forums/showt...hreadid=192404

 

That's how crazy things have been for me. I completely forgot I made that post up above. lol I'm just going to have them measured when I pull them since they're going in to be flowed too.

Ok, so 4% per point. Given right tuning, how safe would a 11.5-12.0 be on the street. I ONLY run 93 octane gas in the car. If I can't get 93 (happened once on a previous car) I get the next highest and a bottle of octane booster.

 

Wont know if its doable until the cam is ground. So your kinda in a catch 22 right now, gotta do some things before others, but cant do those things until other things are done

 

Well, the motor will be in the building process before the cam gets ground, I'm sure. I think I'm just going to shoot for a static compression ratio of an 11.0 to 1.

 

Good idea.