I bought this used about 1 year ago, and finally got motivated to install it. Since I did not but this
new, I have no idea what is included with the kit. I received mine with 2 pristine gaskets attached,
and nothing else. I'm sure there's a better way than how I did it - but it worked for me!
Make sure you have the following:
1: (2) new plenum (doghouse) gaskets (One for the top, and one for the bottom)
http://www.nos4gn.com/servlet/the-232/Buick-Grand-National-GNX/Detail2: New throttle body > plenum gasket.
http://www.nos4gn.com/servlet/the-287/Buick-Grand-National-GNX/Detail3:
Some sensor-safe silicone sealer Install DRY
4: Longer plenum bolts (Stock may strip)
4: Obviously - the powerplate.
Tools:
13MM, 15MM, 8MM, 9/32 sockets, 13MM open end wrench, small screwdriver, gasket scraper, patience..
Procedure:
Remove MAF pipe, up-pipe.
Unplug TPS and IAC (be gentle).
Using 8MM socket, remove the screws holding the vacuum distribution block from the top of the throttle
body. Now is a good time to replace the rubber vacuum sections connected to the vacuum block if needed.
Disconnect the transmission kick-down cable, throttle cable, and cruise control cable (if equipped)
from the throttle body linkage. Be careful with those small clips! You can also remove the cable bracket from the plenum and move the cables out of the way, as an assembly. Use a 9/32 socket for the two small bolts.
Disconnect any throttle body coolant lines (Why do you still have these connected?)
Using a 13MM socket with an extension, remove the 2 throttle body mounting bolts. A magnetic pick-up
tool works great here. GENTLY remove the throttle body. Now is a good time to clean it up.
Using a 13MM wrench, remove the bolt holding the throttle bracket to the plenum.
Using a 13MM socket, remove the 4 remaining 13MM bolts on the plenum.
Gently remove throttle cable assembly and PCV vacuum assembly from the rear plenum mounting bolts.
When clear, using a 15MM socket, remove the 2 rear side studs.
GENTLY remove the plenum from the upper intake. Stuff a rag or something in the intake hole to keep
debris out. Now is a good time to clean up the plenum.
Using a gasket scraper, clean all gasket mounting surfaces on the plenum, intake, and also the surfaces
where the throttle body meets the plenum.
Pull the rag from the intake, and clear a path to make it easier to replace the plenum.
Using your replacement gaskets, apply a THIN coat of sensor-safe sealant to all plenum surfaces, and
the intake mounting area. Most Buick gurus recommend installing the gaskets DRY. It's your car, your choice.
Align all gaskets, and replace plenum. Replace all plenum bolts, just snug, not tight enough to squish
all the excess sealant out. (If using sealant, obviously) Let stand for about 10 minutes.
NOTE! If using the stock plenum fasteners BE VERY CAREFUL. The added thickness of the Powerplate reduces the amount of bolt threads that can go into the lower intake. If you over-tighten these - you WILL strip the plenum bolt holes in your lower intake!
It's best to make a trip to the local hardware store and get longer bolts. The standard non-stud bolts for the plenum are M8 X 1.25 X 25 - an M8 X 1.5 X 25 would be better.
As far as the rear studs - if you think you need them you can get a stud and some washers/nuts, or just use bolts.
Tighten plenum bolts in an alternating pattern.
Take the same care an patience applying sealant to throttle body and front of plenum, and the
reassemble all components.
I don't race my TR, so I don't know if it's any faster number-wise, but my car idles GREAT now, and
seems much smoother.