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  #16 (permalink)  
Old 05-02-2004, 09:47 AM
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If you plan on cranking that monkey up above 6 grand you need at least 0.040" of clearance. Maybe a few more to be safe.

You said the piston was 0.020" in the hole right? 0.020" down the cylinder and knocking the head up 0.030"!
I'd be swapping pistons before the build got any further along. The piston may be designed for large/open chamber heads and you got the small chamber heads. That or the heads have been milled excessively.

Aside from the clearance issues, you'll have some serious combustion efficiency issues. Big blocks have enough problems burning fuel and combustion problems will be compounded by little or no effective quench, 0.060"quench with a 0.040" gasket, and a huge dome interrupting the flow of combustion.

Correct the problem with the pistons' interference and zero deck the block. You'll get the compression you are looking for and more efficient combustion. All that equals more power.


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Old 05-02-2004, 10:20 AM
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Thanks for the advice coldknock . Got so much money in it now im going to have to make what i have work. Piston clears everywhere else .Just one small spot about 1/8inch on bottom side of piston.I have a 427 tall block
820heads 113 cc open port
trw l2308af .060 50cc domes 1.760 ch
3.760 stroke 6.535 h beam rods
chet herbert roller cam int 655 ext 685 108cl dur .257 .267
3500 to 7000 rpm
crane solid lifters
crane gold roller rockers
weiand team g intake
edelbrock 800 cfm carb
thanks Dennis
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Old 05-02-2004, 01:41 PM
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You should lay back the chamber since it is easier to do then cutting the pistons with them in the block,and it wont effect the balance.I do see one more problem.This pistons wont clear .680" lift.Out of the box,the exhaust side is good to about .575" with a cam that has 260 degrees at .050".That is based on old flat tappet figures,but I have a hunch that roller still isnt even gonna be close.I have cut as much as .120" out of the exhaust side of those super heavy slugs to clear a .708" roller.Good luck.
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  #19 (permalink)  
Old 05-02-2004, 08:50 PM
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Sounds to me like you have it in the wrong hole. Double check them.

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