Small CC comp. ratio question on 427
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Small CC comp. ratio question on 427
Let's say you have a 30cc CC C5R head that is designed to be ported and polished and you just don't do it. You take no material out of the CC. How much would the dish (CCs) have to be in the piston to get the comp. ratio suitable for forced induction? 427, LS7, C5R, or whatever. Normal head gasket. More than 20ccs?
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11.5:1 on pump gas and no meth would be very difficult. i am building a boosted 347 and i am going with 8.5:1 CR, because i plan on running big boost on pump gas. i suggest you do not go over 9.5:1 if you are planning on using pump gas on an FI motor.
good luck
good luck
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You will have problems with detonation on an un-ported C5R head. The combustion chamber is rough cast and meant to be finished. That will make for horrible flame propogation and hot spots.
Shane
Shane
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The engine started out as NA. Builder thought FI would be a good idea. I don't know why he didn't port and polish the heads. Looks like it got over looked.
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It will run. Just not well. As stated above, those heads are designed to be worked. The combustion chambers are NOT remotely ready for an FI build. It would be worthwhile to take the heads and have them finished if you are planning on spending money on a FI system.
Just my $.02...
Shane
Just my $.02...
Shane
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PM me. I can either get the heads done for you or put you in contact with our porter to have them finished. It won't be cheap but in my experience, Craig Gallant can make the heads perform to whatever level you require.
Thanks,
Shane
Thanks,
Shane
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Did I post these pictures? I'll have to figure out how to resize them.
Crap, it may be too small to see the details! This CC is as it came out of the box!
Crap, it may be too small to see the details! This CC is as it came out of the box!
Last edited by grb; 05-22-2009 at 09:30 PM. Reason: ADD PIC