From original GM literature (but not in the same document)

Powerglide 235
lift .316"
cam duration: intake 244°, exhaust 244°
overlap 33.5°
LSA 105.25°

261
lift .396"
cam duration: intake 244°, exhaust 244°
overlap 24.5°
LSA 109.75°

late 235
lift ?
cam duration: intake 276°, exhaust 260.14°
overlap 51.57°
LSA 108.25°