[Henry Schmidt]

You can grind the cams to fit as long as the lift on the new cam does not exceed the journal diameter.
The big issue (if there is one) is the base circle. With the 49 mm cams the base circle is larger so on the 3.0 and larger heads, the valve stems are shorter. When you put the 3.0+ cams on a 2.7 or less engine the valve adjusters ends up way too short changing the rocker geometry. If it's too short it can restrict the movement of the elephant foot on the valve adjuster. You can also see the adjuster hit the valve cover in these situations.
You can shorten the valve stem length to restore the proper dimensions but then you would need a lash cap.

If you have the cams on the grinder anyway, why not just grind the cams to suit the 2.7 valve geometry.