The water pump is failing? It often announces its imminent demise with a leak underneath the pump's nose where there is a little weeping hole. That is a sign that the bearing is going and you had better address the pump ASAP. 

Sadly, Plus 8 pumps are a maze. They reflect the timing cover you have and they do not always reflect Rover and Land Rover choices used on the same day of manufacture. They fall into many time eras reflecting the different timing covers used and which vehciles they were used in. 

A. Buick 215s) B. pre-Sd1s (1968-1976) , C. Sd1 (1977-1987) D. 3.9 covers (1991 to 2000 for UK and non-Overseas models), E. GEMS covers from 1998-2000 for Overseas cars and then  F. all cars used GEMS covers until the end of Plus 8 production in 2004.  G. Airconditooned models versus non-aircon modles. Serpentine If in doubt, contact me.   There were also transition interim covers for pumps and some aftermarket fare in electric pumps.

WATCHPOINT: Many LR/Rover V8 water pump variations can be used if the front extended nose of the pump is cut off.  This must be done with some care and the right high speed grinder lest the pump bearing be burned.

There were also transition interim covers (please advise me if you run across one!) and more aftermarket fare in electric pumps.
 

Buick/Olds 215	Buick 215, 300 or 340

Rover 3.5 Sd1 Vitesse Morgan Plus 8 Ready	Land Rover 3.9 (1987-1996 all

In most cases, only one of these pumps will fit your Morgan Plus 8. There is no difference between EFI or carb versions.  The Buick and Olds pump have an oil pump position outlet that sticks straight out and will interfere with your alternator.  The V6 pump is too long to line up the WP pulley with the crank pulley. The later LR versions require a different timing cover (a big ugh!) But Its pulley mount is shorter than the rest, providing more radiator clearance. The Rover Sd1 Part # is ERC474 (Morgan +8 1976 to 1990). 

 It is a single groove chrome pulley used on '69-'85 GM applications with V8 engines.  Its mounting holes are larger so a new set will have to be drilled to get it to mount on the pump.  Because it is a shorter pump, an engine driven cooling fan is more easily fit behind the radiator.

I find these pumps fairly easy to source if I am patient. Consequently, I have piled up a few new pumps for this era on both sides of the Atlantic. If you are stuck, I will spare one to get you up and running quickly. email webmaster@gomog.com The only difference between the non Morgan pumps and the Morgan pump is that Morgan cut the nose off these pumps to get them to clear the crossbar. No problem

There are two other solutions. The first is that these pumps CAN be repaired, contrary to prevailing opinion in the UK. There is no Rover repair kit, but there is one made by for the Buck pump which will do. Alternatively, any professional machinist can mange it. The Buick kit is $35 from vintage Buick specialist or UAP.

The second solution is to switch to the later front 3.9 timing cover with the bigger pump. I tried this as I have a bigger capacity Rover v8. The watchpoint is that some machine work will be necessary to align the later water pump's pulley with the others. The payback is a bigger water pumping capacity.