906 big block valve ?
OK the cam is Comp number 21-223-4 = 477/480
Comp Cams XE268H 'Extreme Energy'
Hydraulic
Single-Bolt Cam Timing Gear
Lift .................... .477"/.480"
Duration ............. 268*/280*
Duration @ .050".. 224*/230*
Lobe Seperation ... 110*
Centerline ........... 106*
Overlap ............... 54*
A Great Street Camshaft, with a slightly rough-idle.
With the Cylinder Heads milled {.035"} you will still enough clearance between the Piston and Intake Valve {2.11"}.