Hey Tony P & EvilDr235. . .

I just had a closer look at the specs on the cam for the 261. 290 degrees of duration? Isn't that 'Stage III Tuning' according to Tom Langdon? Or is this a misprint?

I was comparing these numbers with the valve timing diagrams from California Bill's book . . . his digrams of a 'Super Grind' show a duration 288/int and 285/exh . . . back then cam discussions were valve-open to valve-closed duration (SAE) correct?

Am I perhaps mixing .050 and SAE specs when comparing these cams?

If the table is correct, the 261 cam has only 190 degrees of intake duration above .050 -- but there is an additional 100 degrees of duration that is shallower than that. This makes for shallow ramps running up to and off of the lobe center - a design that is easy on push rods and lifters correct?

As such, I thought that these .050 specs just helped one to see how steep the cam profile is.

Isn't duration duration?
The valve is open . . .


[This message has been edited by stock49 (edited 11-30-2003).]

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