Ages ago a friend threw a set of 272deg cams into an otherwise stock bigport (I think he wrote about it on Toymods.. maybe user "cnic82" or "craigy" about 5 years ago). He said they made a noticable improvement and everything ran fine.

So yes, you can do it. Of course it's not optimal (as Dave says, tunable ECU will help make the most of them), but it should work.

Hen