as usual it seems like i havent read the whole story :P if u say your heads flow after .600+ .. ok ive done something like this before.. first thing you do:
remove springs on the 1" int + exh valves, mount a dial indicator be sure it goes straight angle with the int valve (if u have a test spring add it at this time) replace the retainer and measure the how big ur valve stroke is.. (leave piston at bdc ) when u have the stroke on both valves noted and its over ur cam specs (use the 1.5 or 1.6 rockers?).
next u do: turn engine to tdc, mount the degree wheel on. now u drop the inntake valve onto the piston, how far is this? note it. now u rotate the crank, note the distance every 1 or 2 crank degrees.. do this for both valves be careful do not rotate the crank so the valves go upwards (they may lock up in the notches) now u have made urself a profile of the valve distance per crank degree.. now u can just do some math with the degree sheet from the cam u want to buy and see if u are ok.. i have done this myself and it worked out great. (most rollercams comes with the springpressure noted so u just buy the best/closest springs u get. (i glued on valve stem caps with locktite to have the rocker just a bit away from the retainer, after a machined away what i could.