I have been installing Fierorog's low mount alternator mount and dog bone mount on my 3800. It has been, to say the least, quite a difficult job. This article will explain how I did it.
First of all, courtesy of Fierorog, here are pictures of the parts he supplies (along with various bolts and nuts, not pictured here.
The tensioner shown in the picture above, which you have to purchase separately, is from a 1995 Ford Taurus. Fierorog's alternator mount requires a 1999-2003 alternator, so I had to get one of those also. The 1995 alternator's mounting points are wrong.
You will also need to get a Dorman part no. 47065, which contains the items shown below.
The Dorman parts are needed because the original tensioner, which you must remove, contains coolant passages which supply coolant to both heater hoses in the original GM application. On my car, only one of the coolant passages through the tensioner is used, and the other is plugged, because one of the heater hoses is connected to the passenger side main coolant line under the car.
Here are some pictures of the original tensioner. The first picture shows the "back side" of the tensioner -- the side bolted to the engine.
This view is the tensioner flipped over.
The Dorman parts are used to supply coolant to the one heater hose that was connected to the tensioner, and to plug the other coolant passage. The Doorman part with two red O-rings was prepared as in the picture below. I cut off one of the enlarged ends, and then cut a short piece of heater hose and slit one side of it so I could place it as shown. The Dorman part will be pressed into a hole, and the heater hose piece limits how far it can be pressed. Too far, and it will leak. (Been there, done that.)
I connected about 10" of heater hose to the cut end of the Dorman part, and inserted it into the hole in the upper intake manifold (which used to have a similar piece from the old tensioner inserted in it. See the picture below. The hole is right above the water pump.
To make a plug out of the other Dorman piece, I threaded the small end with 3/8" NPT threads, and screwed in a 3/8" NPT plug. Then I inserted it into the other hole vacated by the old tensioner, and secured it with a zip tie. (I may have to secure the other piece also somehow, but will run the engine to full operating temperature first and see what happens.) The pictures below shows my plug in place, and the dog bone mount with the new tensioner mounted just above it.
This pictures is from above, showing everything mounted (except the dog bone, on order from Rodney), and it shows my new heater hose routing.
I think Fierorog designed his parts for 1999 and newer 3800's, because I had to cut a dip in the bottom of his alternator mount to clear the oil pressure sender on my engine.
This picture, courtesy of Fierorog, shows everything mounted from the side (on a supercharged engine in this case).