These two engines are fundamentally identical. There is no difference in displacement, the designation was merely to indicate that one had DIS and the other had a distributor.

Camshaft/front cover and depending upon the year of the 4.0, the fuel rail may even be retained-if it's non-AEL.

It may or may not need a crankshaft space, but they are easily enough made from an old crank gear.

One note-depending upon the year of the 4.0, you may need to retain the flywheel from the original engine.

 

The D&D site has tons of stuff like distributors and the drive gears and such. I like the valve covers that they have to dress up the 4.0's as well.

The swap with another member could also be a good move.

If you add your location in your profile, you may find others nearby that are RoverHeads.

 

D&D's stuff is nice but most of it is not cheap

 

I have the cam gear, the spacer and the distributor drive gear in stock as well.

Mark will likely have a suitable camshaft, I don't have any in stock-trust me, you'll want to replace the camshaft as it is likely badly worn.

 

Thank you guys for the reply! I think that I will take the front cover off the 3.9 and place it on the 4.0. I would like to know why I would need another cam gear, spacer, and distributor drive gear? Wouldn't the one off the 3.9 fit?

 

What about the existing wear? You want it to run good don't you?

 

Yes, won't I have those pieces from the 3.9 though?

 

Gears wear (as do any mechanical part in intimate contact with another moving part).

Cams wear as a matter of functioning.

You may be able to disassemble and inspect but can you determine acceptability?

 

Or just fill it full of every Miracle Cure you can find.............

There is a multitude of stuff on the markt that claims to fix almost anything and everything.

 

I converted a 4.0L to run on a four barrel carb a number of years ago. I would NEVER try to go forward with the injection system. By that I mean 14CUX to GEMS. The later conversion is way to much trouble. Use the front engine cover so you can install your distributor, get a new cam and lifters (you'll need them anyway), block off the hole in the back for the crank sensor and you're pretty much there. Drop the 14CUX intake and plenum on the 4.0L long block and you're set.