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Old 06-07-2021, 09:36 PM
rod cole rod cole is offline
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Default recommended spring pressure

comp 4136b intake 4137b exhaust 270 duration at .050 and .430 lobe lift approx .700+ at valve thanks Rod

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Old 06-07-2021, 10:51 PM
tom s tom s is offline
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What does the maker recommend?Tom

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Old 06-08-2021, 05:55 AM
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steve25 steve25 is offline
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What heads are you running?

What lenght valves?

What's the max rpm this motor will need to spin to?

What ratio rockers will be used?

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Old 06-08-2021, 06:28 AM
Steve C. Steve C. is offline
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A fwiw, and information offered for general interest only. Joe Sherman posted this on Speed Talk involving a aggressive Comp RT lobe with well over 0.700" lift....

“Currently on dyno with a small block RT intake with a 1.65:1 rocker and 128g valve (I know it's heavy) and with a PAC 1385 set at 275lb seated and 660open. This thing is out of control by 7700...”

Note a small block Chevy valvetrain in use in that comment. Already eluded to in the above post, and that being the valvetrain mass and the RPM level involved here.


.

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Old 06-08-2021, 11:20 AM
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Scott Stoneburg Scott Stoneburg is offline
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I would definitely check the manufacturers recommendation. But a general number would be 325-340lbs on the seat and 650 lbs open.

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