[lordhelemt]

Recently replaced the 3.9 in my nas 110 with a 4.6, it is a worthwhile swap. Simple and very easy swap. You will want to replace the ecu with one mapped for the 4.6. I was getting a little bit of hesitation using the old 3.9 prom above 3k rpm but now it's running great.

 

[lordhelemt]

If you’re doing the work yourself I’d just get a gems 4.6 takeout with good compression numbers. Replace the cam, lifters, and timing chain. Grind the teeth off the old timing chain gear (the one for the crank) to use as your spacer. Use your old front cover, pull the metal dowel on the back of the crank and do what you want with your heads (just use the correct gasket). That’s basically all you need to do for the conversion. It is that simple. Bosh motor will work as well but may not be as stout (I have no personal experience with bosh blocks). When doing my 4.6 I was a little concerned if it was going to be this easy but it really is that simple. The most difficult part of the build was cleaning all the bolt on parts.