This car was the last year that the infamous HT4100 was used. It's got 270k miles on the clock and everything on the car (paint, interior, transmission) is still in good condition except the engine. The engine has had a noisy valve train for a long time but lately, it has been getting progressively worse to the point that everybody could hear it coming from several blocks away. Also, the rated 125 hp was more like 50 hp. The engine would struggle in 2nd gear with the pedal through the metal going up Snoqualmie pass and passed by semi's that were carrying a full load. By the time you got to the top of the hill, 25 mph was as fast as she would go. We did open up the valve covers to inspect the rocker arm support fixtures for cracks and they were fine. So most likely, the camshaft and cams were wiped out. Also, average fuel economy had dropped down to 12 mpg. Even my 1990 3/4 ton Suburban could actually do better than this.
Anyways, long story short, we were given a 4.9 out of a 1992 Seville with 80k miles on it. The decision has been made to put this engine in place of the 4.1. The plan of action is the following:
1. Block off all the injector ports on the 4.9.
2. Bolt down the 4.1 throttle body to the 4.9 intake manifold
3. Transfer all the accessories over to the 4.9
4. Use 350 Chevy injectors
5. Bolt the stainless steel 4.1 exhaust manifold onto the 4.9
6. Use the 4.1 distributor
7. Modify exhaust system to have 2 glass packs in series and replace the back muffler with a chambered muffler.
With this 4.9