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edelbrock head decking question

Posted By: dcr

edelbrock head decking question - 05/12/11 09:44 PM

What is a safe amount to remove from a edelbrock performer head trying to maximize compression is it possiable to go to a 65 cc chamber? Anyone know how much each say .010 is good for Thanks
Posted By: Sport440

Re: edelbrock head decking question - 05/12/11 10:57 PM

If its a BB the average cc removal is 2cc per .010 cut. Dont know about the SB, except that they will remove less cc,s per every .010 cut.
Posted By: dcr

Re: edelbrock head decking question - 05/12/11 11:01 PM

They are big block at 84 cc now so .100 should net 74 cc?
Posted By: The Duster

Re: edelbrock head decking question - 05/12/11 11:25 PM

I believe that would require .050 not .100
Posted By: Sport440

Re: edelbrock head decking question - 05/12/11 11:25 PM

No, thats 2cc per each .010 cut A .050 cut would get you about 74cc chamber, or 5 x 2 cc for a 10 cc reduction. Also, as the chamber gets incrementaly smaller, so does the cc loss per each .010 cut.
Posted By: WILD BILL

Re: edelbrock head decking question - 05/13/11 12:25 AM

Mine started out as the 84 cc heads.

We originally cut .090" off em and the chamber came in at 64.6cc's

I know after the last failure that we cut them another .010" But I forget what the final chamber volume ended up at and I don't have the build sheet in front of me.
Posted By: dcr

Re: edelbrock head decking question - 05/13/11 02:11 AM

Thanks for the replys I got to many numbers going through my head sounds like I can get 65cc out of them with out much trouble any reliability issues with that big of cut or major intake alighnment problems They are max wedge ported also.Need as much compression as possiable im going to try e85 and want to reap as much of the benifit as I can .Little 432 at 65 cc good for 12.5 with piston .005 in hole according to compression calculator.Thanks again
Posted By: WILD BILL

Re: edelbrock head decking question - 05/13/11 02:50 AM

The head has plenty of thickness to cut .100" off it.

However, it did require machining the intake to fit.

IIRC we also had to elongate the holes in the intake to aid in ease of instalation.
Posted By: Sport440

Re: edelbrock head decking question - 05/13/11 03:20 AM

Like Wild Bill stated, the Eddy head is plenty thick, .625 to be exact. Hows that compare? MP boasted about the old Stage 6 head being .450 thick, with a max recommended .100 cut reducing that to .350.

If you cut your head that far, you will still have a thicker deck .525 thick then a uncut MP stage 6 head @ .450. But you will need to address the intake issues and the extra reduced P/V clearence that will occur.

If you shave the heads intake surface the the respective ratio of .0123 off the intake for every .010 off the flat. The heads intake surface will be recessed pretty deep from the Vally pans rail causing a gap problem. You will need to address that some way.

Cut the rails, stack paper gaskets, take less off the intake side of then recommended, cut the intake itself. etc, etc.
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