Mounting the Engine
The 4.9 will fit nicely with the transmission in the stock location. If you are using a Fiero transmission, you are one step ahead, if you're using a 4T60 or 4T60E look here to find out what you need to do to mount it properly. With the transmission loosely bolted to the cradle, and the engine bolted to the transmission, it's fairly easy to determine where the engine should be positioned. Many of the transmissions will have a small circular hump on the end cover. This point along with the center of the crankshaft bolt can be used to position the drive train so that it is level and straight by measuring down to the frame rail and front to a common point on each side of the cradle.
My main engine mount bracket is cut from 1/4" steel plate, designed to be used with a GM transmission mount. The long oil pan of the 4.9 prevents the possibility of using the stock Fiero engine mount in it's original location. The mount I'm using here is Energy Suspension part number 3-1108 multi-application RWD GM transmission mount. It has a built in steel safety interlock in case of failure of the polyurethane. They sell for ~$20. I will provide patterns for this bracket as soon as I have time to scan and upload them.
Another 3-1108 mount is used on the front side of the engine to help stabilize the engine. It bolts between the stock Deville engine bracket and a simple piece of angle iron welded to the cradle.
There is also a torque strut going from the rear cylinder head to the cradle. This particular one is made from a GM rear suspension link.
Here are some pictures of one that I did a few years ago using the stock Cadillac engine mounts. This requires that the cradle be modified.
