rebuilding my 63 340hp and inside is a solid lifter cam, trying to ID, only numbers on cam are "039271.40". Would like to know what I have before I trash it, it is in good shape but not going to reuse.
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Re: 63 340hp, camshaft ID
Are those numbers die stamped or embedded in the casting? Where are they located? A photo would help. Look to see if "CWC" is embedded in the casting.
A real period Duntov cam would have 6098 embedded in the casting These are the last four digits of the finish machined camshaft part number, 3736098. The number usually associated with the Duntov cam is 3736097. This is an ASSEMBLY consisting of camshaft and indexing pin. All other OE camshafts follow this numbering convention.
This camshaft was designed in 1956 for the small port 265/283 engines. It essentially became obsolete when the big port heads were introduced in 1961 on the 315 HP FI engine.
The best OE high performance mechanical lifter camshaft of the era was the last one designed, the LT-1 cam. It uses the L-72 lobe, on a smaller base circle on the inlet side and the 30-30 lobe on the exhaust side indexed four degrees earlier with a narrower LSA for less overlap than the 30-30 cam giving about the same effective overlap as the Duntov cam and less than the 30-30, which has so much it kills low end torque making these engines pretty soggy down low.
OE cams can be ground by Elgin and Howard's cams.
The LT-1 camshaft part number is 3972182, cam/pin assembly 3972178.
Do not use springs any stiffer than OE 3911068/Sealed Power VS 677. With proper setup these springs yield a valvetrain limiting speed of 7200 with 80-84 pounds force on the seat, about 200 open with a rate of 267 lbs/in. All higher force/stiffer springs do is increase the chance of lobe/lifter failure.
If you want to measure and post the heel to toe dimension of a couple of inlet and exhaust lobes I can dig out the OE data and see if your measurements match any OE mechanical lifter cam.
DukeLast edited by Duke W.; December 6, 2024, 11:19 AM.
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