That's a different grind than the 4 speed cam. The 4 speed cam was a dual pattern, just like the auto cam. It had more duration though and it may have had more lift too.
Yeah, here it is from
@krazykuda right out of the 1968 service manual.
68 340 4 speed cam:
276°/284° duration
.444"/.453" lift
Int open: 26° BTDC
Int close: 70° ABDC
Exh open: 78° BBDC
Exh close: 26° ATDC
Overlap: 52°
Per the 68 factory service manual