In my opinion there is considerable confusion in some of the posts in this thread.
A couple of things.
Just because a cam has the same opening, closing, and lift as another cam does not make it the same cam.
Please read the article titled Valve lift profile design at this location.
http://www.profblairandassociates.com/RET_Articles.html
To quote from the article
"Those of you with a mathematics bent will realise that the
numerical differentiation of the valve lift-degree profile will
produce a velocity-degree curve; the differentiation of the
velocity-degree curve gives an acceleration-degree profile; and
the differentiation of the acceleration-degree curve gives the
jerk-degree characteristics. {Just as the velocity of a car is the
rate of change of a distance-time curve and acceleration is the
rate of change of velocity}.
It will also be remembered that, courtesy of Isaac Newton,
acceleration is directly related to force and hence jerk,
which is the rate of change of force, is an ‘impulse’ or
‘hammer blow’. "
Peter Williams designed several cams including the 4 S and the PW3. The PW3 was designed using a computer at Warwick university and was very probably the first Norton cam designed using modern cam dynamic mathematical techniques. He specifically designed the PW3 to minimise this "hammer blow".
Jack Wiliams - the engineer who developed the AJS 7R in the late 1950s and Peter Williams are father and son.
http://en.wikipedia.org/wiki/Peter_Will ... cyclist%29
Peter knew a very great deal about his fathers work and spent several hours telling me about the issues his Dad had with cam design on the 7R.
The inlet cam lift at TDC should be set on the push rod. Peter designed the cam for a wide power spread. But as I said in my first post he recomended advancing it 5 deg if you wanted top end power.
If you bought the cam from Mike Hemmings ring him up for advice. He may even pass your questions on to Peter Williams.