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Old 03-01-2014, 12:51 PM
Senior Member
Join Date: Jan 2006
Location: La.
Posts: 2,890

Originally Posted by ajk
Zip, clue me in a little further if you don't mind on the Rockwell testing. Is there standard # that these are compared off? I see 45/47 and 39/41 etc. I don't want to sound as dumb as I am but what does that indicate? Thanks Al
The lower the number the softer the metal, so the newer cam was 7 points softer than the older cam. The older cam i tested was about 11 or 12 yrs. old and the newer cam was 4 yrs. old and had 4 flat lobes on it.
I had run the older flat tappet cam in my 406" motor with 135 lbs of spring rate. The newer one cam out of my El Camino, with 115 lbs of spring rate with about 3,000 miles on it.
The only compaeison was that todays cams are not heat treated as good as the older cams were, and maybe not even as good of cast iron.

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