Hi All

New questions:

I was wondering if people could explain to me how lift enters into an equation on cam profile. Why does it promote breathing and increase horsepower on a big block 440? Also are their any draw backs to high lift on the street?

For instance it was sugessted I could wring some power out of my mildly builr 440 by going from a 1.5 stock rocker to a 1.6 rocker.

Thanks

Mike

lift is free horse power and is your friend. the only draw back is more lift you got it makes it harder on everything! valvetrain, pushrods, springs to keep up.....

to a point the further the valve is out of the head the greater the flow through the head but duration (time the valve is open) is just as important. you will see most durations listed a "at .050" which the general idea is that the valve doesn't start moving air till then and lifts/timing events below that are more difficult to accurately measure. using the higher ratio rockers will affect duration as well as lift. if you use the higher ratio rockers you need to make sure there aren't any other conflicting factors such as piston to valve clearance or retainer to guide and are the springs up to the task. overall the higher ratio rocker makes the cam look bigger to the engine.