So I cant figure out this ticking noise and before I rebuild the top end I want to try and use seafoam. I watched a video where they poured half a can slowly down a vacuum line and it blew out all the carbon. WOuld this help with the noise possibly? or is it bad to use?

 

Go for it, but use the whole can.
If that does not help then try Marvel Mystery Oil in the crankcase for 500 miles and then change it and switch to a diesel oil, like Shell Rotella 15w-40.
That is what I use and my truck purrs like a kitten.

 

i just changed the oil with delo 400 15w40 but maybe ill try the marvel mystery oil. If neither of this works than im about to just pull the motor and do a 4.6 shortblock swap

 

The only difference between the 3.9 and 4.6 (besides the electronic ignition) is the guts.
The 4.6 block is the biggest piece of crap Rover ever made, there have been no less than 3 that have blown up on this forum in less than a year.
Do a 4.0 swap not a 4.6.

 

ticking is most likely a lifter the marvel might free it up

 

is the 4.0 based of the buick motor? if im gonna take the time to do a rebuild I want to add a little more power as well. what year do i get the 4.0 out of

 

Your 3.9L is also. I do not cite Wiki as gospel, but it is quick and easy.

http://en.wikipedia.org/wiki/Rover_V8_engine

 

You can swap a 4.6 and it will be fine. The 4.6 is the same as yours, just stroked. You will need to find one from an old Rangie to get the distributor drive. You can find a 4.2 as well. You will not find a 4.0, pretty sure a 3.9 and 4.2 are your options unless you go new.

The 4.6 Spike was referring to is a different animal. Disregard that.

Roverparts.com has a direct swap 4.6 distributor drive long block. Kinda pricey, but it will drop right in. The only way to get more displacement out of yours is to swap crank, rods, and heads. (cam as well to get more lift).

Rover bought the design from GM way back and it has been changed so the buick parts won't fit anymore.

For Seafoam, it will clean out your intake valves, but the pre-96 engines did not have carbon cutters on the exhaust valves, and that would be where one would be sticking. Seafoam won't get there.... Make sure you are running high octane fuel, and I would suggest some BG44K every other oil change.