8) Next, I used a dremel with 1 1/2" EZ Lock cutting blades (an EZ Lock fastner is required to use these blades, but it is worth the expense because it is so much faster to change the blades). These blades do a good job, but they break easy, so go slowly, and don't apply too much pressure. You will want to have 10-20 blades on hand.
Remembering how easy the center plate broke with the hammer, I decided to use a pair of vice grips to grab and break any larger areas that remained (were I couldn't reach with the hammer). This worked very well.
Once I got as much as I could, I went back to the cutting bit on the drill and smoothed up all the cut edge of what was once the center divider. I also did some more smoothing on the runner edges because I could reach them better now that the center divider was gone. Then I used a course brass wheel to remove any burrs and other material that could later become dislodged and get sucked into a cylinder. Pass your hand around the entire inside of the intake and make sure it is as smooth as possible everywhere.
9) Next, clean up the injector bosses. You want to remove a little material around the outward facing edge of each hole. This gives the injector stream a little better ability to make a good spray into the combusiton chamber. Without this, part of the spray can hit the edge of the injector boss hole, and then drip down into the cylinder. Be very careful not to remove too much. If you cut upwards into the injector hole too much, you can cause the injector o-ring to not seal good. If you cut to much away from the outside edge of the intake, you will be cutting into the intake manifold gasket surface. I used this rounded grinding tip attached to a dremel as you see here. It was the perfect size and shape for the cut I was trying to make.
From the other side, I used this small brass wheel on a dremel to clean out any dirt and grime that is in the injector holes. This gives a nice clean surface for the o-rings to seal against when you install the intake.
Here is the finished cut:
Repeat the same cut on the other runner pairs
5) Next, if the intake you are modding has a center divider, cut the ends as show below. Be careful as you get near the bottom because it is easy to hit the tip of the blade as it reciprocates. You may have to flip the intake over and make the same cut, but from the other side to get a deeper cut. Repeat on the other end of the center divider.
6) Next, I started smoothing up the runner ends. You can do this now, or after you remove the center divider. I wanted a break from the sawzall, so I started on them here. The idea is to make the cut edges smooth so air can flow into the runners without generating turbulance. I used the drill tip you see in the picture. It did an amazing job of removing material and was easy to control. I'm not sure what it is called as I just had it laying around at home, but I saw ones just like it at Napa and at home improvement stores. I used the trigger lock on the drill so that it didn't require my finger to keep it running. This made it easier on the hands and easier to control the drill to slowly cut the material until the surfaces were nice and smooth. You can also use a metal hand file to get any other areas that might be too hard to reach with the drill.
Repeat on all the runners until they are all smooth both on the outside and inside edges.
10) Next, I used a brass wheel attached to a drill to clean up all the mounting surfaces (thermostat, belly pan, throttle body, etc...). Then I used the brass wheel on the entire outside body of the intake. This gave it a nice shine and removed any dirt and grime that had built up on it over the years. If your so inclined, you could also paint the outside of the intake with high temp paint.
11) Look into the runners from both ends with a flashlight. If there is carbon buildup or other debris, it is a good idea to clean it out. I used the Mopar Combustion Chamber Cleaner sprayed into all the runners. I let it stand in there for a couple of hours. Dump the cleaner out, and spray a powerful stream of water into each runner to dislodge any other debris that may have built up in there over the years. Repeat as necessary. When you are satisifed that they are clean, it is time to give your intake a bath.
12) Fill a large plastic tub or even a bath tub with water. Dunk the intake into the water repeatedly. Use a soft brush or a fine brass brush to gently scrub the entire intake, inside and out. This will remove all the small slivers of aluminum that were created as you were cutting and filing on it. I then removed it from the tub and used a hand held water hose to wash it out thouroughly, making sure to get inside each runner, in the injector holes, and in the coolant passages. You want to get it as clean as possible. Let it air dry and check it for cleanliness. Repeat as necessary.
13) I then installed all new hardware. This included a heater hose inlet nipple, thermostat housing, IAT sensor, waterpump bypass hose nipple, and coolant temp sensor. Some trucks use two coolant temp sensors as mentioned earlier. Others use only one. If your intake had two ports, but your truck only uses one, just buy a small plug to plug the hole for the other coolant temp sensor hole. Use high temp thread sealant on anything that you are screwing in to the intake. Also, you may need to block off one or more of the vacuum ports. Notice in the pictures below that I had to plug one on the driver side of the intake so that it matched the number of vacuum ports on my '99 intake. These small rubber caps can be purchased at most auto parts stores.
14) Lastly, install the new belly pan and gasket. I highly recommend using the aluminum plenum pan kit that can be purchased from Hughes or APS Precision. Follow the instructions that come with the kit to install the new belly pan.