The 401 had a different cam than the 304/360. According to the FSM for my 77 Cherokee, the cam specs are:Originally Posted by Dusty
304/360 cam:
Cam lobe lift: 0.286 inch (with 1.6:1 rocker, you get 0.4576 inch)
Intake valve timing: open: 14.75* BTDC; close: 68.75* or ABDC
Exhaust valve timing: open: 56.75* BBDC; close 26.75* ATDC
Valve overlap: 41.50*
Intake duration: 263.50*
Exhaust duration: 263.50*
401 cam:
Cam lobe lift: 0.286 inch (with 1.6:1 rocker, you get 0.4576 inch)
Intake valve timing: open: 25.57* BTDC; close: 90.75* ABDC
Exhaust valve timing: open: 80.80* BBDC; close 42.75* ATDC
Valve overlap: 68.32*
Intake duration: 296.32*
Exhaust duration: 303.55*
You can see that there's just a little bit of difference between the two cams...