H.O. Vs. Non-H.O.

[Phil Ossifer]

Help please,
Other than the roller cam; What other differences are there between the H.O. 302ci engine used in Mustangs and the one used in say, a Mercury Grand Marquis?

A couple of years ago I swapped in a GT-40 long block into my '89 Mustang. Very easy, no problems. Now I want to do the same to my '89 Merc which has the non H.O., non-roller cam 302.

Is is possible or would it be too much trouble? I just want a few more ponies for the old Merc (which is in mint condition).

Thanks,
Phil