GM stock cam differences & identification

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vairguy63
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Joined: Tue Dec 05, 2017 9:16 pm
Location: Oceanside, CA

GM stock cam differences & identification

Post by vairguy63 »

After reading Bob Helt’s The Classic Corvair, I’m wondering if there’s a way to tell which of the 9891 cams got the updated ramp profiles to be more like the 2304 cams. I have several 9891 cams but they vary with their GM stamp wildly. I have some stamped GM 3 all the way to GM 17.

I assume the smaller #’s are the earlier style but does anyone know what stamping # indicates the change in profile?

Someone hopefully has profiled these cams and knows. Very curious... Thanks


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vairguy63
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Joined: Tue Dec 05, 2017 9:16 pm
Location: Oceanside, CA

Re: GM stock cam differences & identification

Post by vairguy63 »

Maybe someone has disassembled a stock ‘66 or ‘67 140 and noted what GM# the 9891 cam that was in it?


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