How much wider are 5.4's over 4.6's. I have deck height differences so I can estimate height differences.

 

since it's a 90deg v8 you should be able to calculate the width fairly simply thanks to some dude named Pythagoras. It ends up about an 3/4 inch wider on each side.

Using bassmans wonderfully simple representation of pyth's theorem you'll get .84" roughly. 3/4" was off the top of my head.

 

Or 2*(deck height*sqrt(2))/2=width and compare the answers for both engines. Note that cos(45)=sqrt(2)/2. Good old trig and geometry...