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Author Topic:   a ? for steve.
rickb33
Dirt Full Roller

Total posts: 47
posted May 06, 2003 09:51 PM
i'm building a 3.5625 stroked chevy for a my car.rules are stock two barrel manifold,and the 2bbl rochester can be modified which is already done,500-525cfm.going to run 64cc heads,with a dished piston,9.5to 1 compression ,9.6to1 being max.the track is a 5/16 mile oval(tight turns) so full throttle is only for 5-7 seconds.should i run a 180cc,or 200cc intake runner.also,hydraulic cam,no lift rule.1 5/8 header tube.also,would 2.02/1.60 be to big a valve on this type of short track engine.max power out of turn is what i'm looking at.rpms with current 355,are 6700-6800.

sdhnc29
Dirt Freak

Total posts: 470
posted May 07, 2003 08:49 AM
In pretty much every scenario you would want to use the 200cc heads w/the 2.020"/1.600" valves . The 180cc heads will give a slight increase in velocity , which will result in a minimal gain in low end torque . Unfortunately in every case , the air velocity gain and resulting low end torque gain occurs below 2,500RPM , well below any racing RPM range for a circle track car . Since your going with the 9/16 stroke , you will see the low end torque lost to the larger head gained back . Ultimately you should produce about the same low end with the 200cc head's , plus more mid and top end power . At any rate , this motor should quit producing power by about 5,500rpm due to the 2 plane intake manifold and 2bbl carb .

Steve

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

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