I thought about doing the same thing with my 67 FB. But I decided against it because the 5.4 is a wide and tall motor. And the 5.4 is infamous for blowing spark plugs out. A friend of mine with a 2001 lightning had one blow out just recently, which was neither fun or cheap to fix. Nice idea, but what I would do is take the freebie and sell it to get a stroked 351W. You could also get a 351C and fuel inject it just to be different.