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I am building a chart showing the different cam timing - does anyone know the specifications for the stock 390 2bbl cam? Or can you point me in a direction where I can find out for myself?
69 2v works for me, or a 72. Christ's book gives the lift, but not the opening and closing. I see he lists a 390 2v and 4v for the pickup years 1968 through 1976. That one would be ideal as it is the one most of us have stock.
Crain Cams gives their opening and closing at 0.004 in and the industry standard 0.050 inch. I would like to be able to compair these numbers with the stock cam.
Thank you - I had not considered the valve springs - are you saying that the higher lift performance cams compress the springs more, or require stiffer springs, and therefore take more power to operate?
Obviously they add more power than they take, but would there be an economy hit when you go with a performance cam that needs to be accounted for?
Yes, if your replacing your cam with a new one. Most cam's have matching springs that are recomended by the company. As long as your within the specs of the factory spring ratings with your new cam stock replacements would be fine. But most cams today are higher lift and duration with smaller lobe centers so check carefully. I can't really comment on economy. Perhaps someone will chime in and offer their input on a nice street cam that's economy minded. I've always gone for power myself. G.