Measure the height of the 5.4 vs the new engine. If the height of the new engine is shorter, you have a 4.6. The deck height on the 5.4 is 10.079" The deck height on the 4.6 is 8.937".

All Navi motors were 5.4, either 2v or 4v heads.

I definitely wouldn't ... Login to read more.