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Piston Compression Height Comparrisons
Posted 11 January 2004 - 02:21 PM
I am bulding an EA81, N/A engine, shared intake and shared exhaust engine. I am going to have larger intake and exhaust valves installed and I am going to use one of the New, not regrind, Ram Air camshafts and high performance spring kits. I will be running a single Holley/Weber carb.
I have access to a salvage yard that has an EA71 as well as a SPFI EA82 engine that are mine for the asking. So I am trying to use the best of all worlds without buying custom made stuff,
Posted 11 January 2004 - 02:51 PM
I have physically seen the difference in the height of the EA81(1800) and EA71(1600) pistons. The difference is in the pin height in relation to the top of the piston. There is a difference but it is slight. It will increase chamber volume but I think the fact that most also deck the heads this may lose some of it too. I am running two different hi-per motors with different cam profiles. One is more torque and one is set up for higher RPM and horsepower. Most of you HP is going to come from your cam regardless of which pistons you use.
I will try to find the numbers for you in the FSM but it may be a while before I can post that info.
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