Component Swap

I actually started the swap after I finished modifying the radiator support. I really didn't feel like reassembling everything knowing that I would just be taking it back apart in the near future. I started by removing the TBI unit from the 4.3. I decided to use the Throttle body from the 4.3 and the fuel pressure regulator and injectors from the 350. This would allow me to loop the accelerator cable around just like it is on the 4.3. It also allowed me to use my throttle position sensor and wiring harness from the 4.3.

The next step was to remove all of the accessories from the 4.3 and bolt them up to the 350.

Here is the 4.3 missing the AC compressor, water pump, TBI accessories, etc...

Here is the 350 with the AC accessories in place.

4.3 Coming Out

200,000 Miles and it never left me stranded.

As you can see, the 350 is significantly larger.

350 Going In

This is the first test fit. At this point in time, I realized that I needed to:

• Modify the AC evaporator housing
• Move the computer wires where they go through the firewall
• Relocated the steering column

This is the second test fit.

This time I needed to:

• Bore out the motor mount to allow the bolts to go in easier
• extend the computer wires as much as possible. The need to go forward and around the AC evaporator housing to clear the exhaust manifold.
• elongate the holes on the drivers side motor mount. The mounts set the engine rather far to the passengers side. Slotting the holes a little more will allow me to mount it closer to its stock location.

This is how much room I have between the water pump pulley and the electric fans with the tranny set back 1/2 of an inch.. Remember, I made extensive mods to the radiator support to provide such clearance.

Almost Done

The motor is now in permanently and running. It actually started up really quickly for having sat on an engine stand for over 6 months. Everything seems to fit with sufficient clearance. There is about 3/4" between the water pump pulley and the electric fans. There is about the same amount of clearance between the steering column and the exhaust manifold. I did not have any exhaust system installed other than the manifolds when I started it the first time. It sounded awesome. I did not run it very long as I have been told that you can warp your valves by running without an exhaust system. When putting everything together i decided/realized that I had to do the following things.

• Cut out a 2" x 7" hole in the radiator support for cold air intake.
• Mount the horn on the fender(there is no room where it used to be)
• Put wire loom on fuel lines and tranny cooler lines(I did not want them to rub through and leak on anything)
• Build a Y pipe(cut weld, cut weld, cut weld, etc...)
• Tighten Motor mount plates(so engine can't slide forward and back)
• Re-align hood latch. It must have been moved forward a little with all of the radiator support mods.
• Build an extension for the oil filler hole(I shortened the one from the 350. The hole was covered by the air filter)

The first run

Well, I finally finished enough of the Y pipe to drive it to the end of the driveway back. Nothing broke, there were no leaks, and the engine was very smooth. Unfortunately, it did not feel that quick though. I think that this is because:

• I still need to adjust the timing
• I still need to adjust the TV cable
• The O2 sensor was not installed so the computer was guessing the air/fuel ratio
• I bent the firewall back too much under the gas pedal(oops). Therefore, I was not able to give it full throttle.
• Our driveway is gravel. I think that the tires were spinning(exhaust was too loud to tell)..

I also noticed that the loom on the wires near the exhaust manifold started to melt. I built a little heat shield and it seems to have worked really well. The wires only feel warm and not hot after the engine has been run at temp.

The second run

I set the timing, adjusted the TV cable, finished the exhaust and bent the firewall back. Then I took it for a little ride. It ran great until the check engine light came on. It was reporting a code 43 which points to the ESC circuit. I was a little suspicious of the knock sensor because I had mounted it on the motor mount plate and the wire connector pressed up against the frame when I hooked it up. I relocated the knock sensor to where the fuel pump would go on a non fuel injected vehicle. I basically made a fuel pump block off plate, tapped the center of it and screwed the knock sensor in. Everything seems to be working now. When I got back I noticed a small oil leak. It seems to be coming from where my rubber hoses connect to the old 4.3 aluminum hoses. I double clamped these connections and they seem to be working now..