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400 30 over, 12.4 to 1 with 67cc heads-665 lift solid roller-920 HP carb-dart single plane

Piston OD is 4.151 and SRP recommends a min of 4 thou clearance. Drag race only motor with maybe 575hp where would you as an engine builder finish the final hone at,taking into consideration NO N2o, heat expansion etc.????
 

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400 30 over, 12.4 to 1 with 67cc heads-665 lift solid roller-920 HP carb-dart single plane

Piston OD is 4.151 and SRP recommends a min of 4 thou clearance. Drag race only motor with maybe 575hp where would you as an engine builder finish the final hone at,taking into consideration NO N2o, heat expansion etc.????
I dont run srp pistons but have been told more than once that material and design of that piston to stay close to min clearence.As stated im not claiming to be an expert on them.
 

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Impossible to decide without the job in front of me, but likely somewhere between std oversize to .001 larger. Gotta Gotta Gotta use torque plates on that block.
 

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Torque plates are a necessity when building any performance engine. There is no reason to increase piston to wall clearance any further than the minimum that is recommended by the piston manufacturer, as long as the cylinders are properly prepared. Hone finish depends entirely upon the type of rings being used. "Most" high performance ring sets use ductile iron top ring with plasma moly facing, reverse-twist, tapered grey-iron second rings and three piece oil ring assembly. For these rings a smooth cylinder wall surface is recommended, which is usually obtained by plateau honing.
 

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Torque plates are a necessity when building any performance engine. There is no reason to increase piston to wall clearance any further than the minimum that is recommended by the piston manufacturer, as long as the cylinders are properly prepared. Hone finish depends entirely upon the type of rings being used. "Most" high performance ring sets use ductile iron top ring with plasma moly facing, reverse-twist, tapered grey-iron second rings and three piece oil ring assembly. For these rings a smooth cylinder wall surface is recommended, which is usually obtained by plateau honing.
whole bunch of "maybe" in that paragraph....
 

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Torque plates are a necessity when building any performance engine. There is no reason to increase piston to wall clearance any further than the minimum that is recommended by the piston manufacturer, as long as the cylinders are properly prepared. Hone finish depends entirely upon the type of rings being used. "Most" high performance ring sets use ductile iron top ring with plasma moly facing, reverse-twist, tapered grey-iron second rings and three piece oil ring assembly. For these rings a smooth cylinder wall surface is recommended, which is usually obtained by plateau honing.
There is no reason to increase piston to wall clearance any further than the minimum that is recommended by the piston manufacturer
In a perfect world we have built cirlce track engines for 35 years or so and have found that an extra .001 works much better then fitting to the manufactures spec.

Reason being alot my customers don't get the engines up to temp before the green flag drops and the pistons will expand before the cylinders do.

We just pulled down a super late model engine with 4 years or racing and the skirts looked great as well as the cylinders.
 

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Don't forget that about .0005" will wear off the bores in the first 1/2 hour of running,so if you want .0045" piston to bore clearance(which I have run successfully with SRP'S) then set the clearance initially at .004".
 
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