Cam timing - Spitfire (again)

[LARRY.SNYDER@monsanto.com]

     OK, I'm pretty certain I have the camshaft correctly installed in my 
     1970 Spit engine. The question now is, how can I make certain that the 
     cam is aligned properly? Somehow the marks on the sprockets just don't 
     convince me...
     
     I would like to check it by measuring how far before TDC the intake 
     valve closes (or is it how far after TDC the exhaust valve starts to 
     open?)
     
     Does anyone have the numbers for standard Spit cam timings?
     
     Thanks!
     
     Larry in St. Louis