Here’s the numbers I came up with when I reverse engineered the cam specs from a low mileage ’57 "D" code which uses the same cam as the “C” code.
Intake:
Actual adv dur – 259°
Actual dur @ 0.050” – 208½°
Actual dur @0.100” – 180°
Actual lobe lift - .269”
Shop manual adv dur – 256°
Shop manual dur @ 0.100” – 176°
Exhaust:
Actual adv dur – 255°
Actual dur @ 0.050” – 201°
Actual dur @0.100” – 175½°
Actual lobe lift - .282”
Shop manual adv dur – 256°
Shop manual dur @ 0.100” – 178°
Camshaft was ground on 112.375° lobe centers.