In the near future (like next weekend) I'm going to tackle pretty much every replaceable item on the engine of our Buick. I have some questions before I get started...

1. What are the best plugs for a non-modified L67? I really like NGKs, but are the TR55s recommended for SC, too (I know they're preferred for NA)
2. What'* the best way to do a coolant flush? And, should I do it before or after the LIM gasket job? I want the Dex out. What should I replace it with?
3. Where can I find a new by-pass elbow? Anyone have a part number?
4. Should I replace the needle bearings in the SC? If so, how?
5. Should I replace the SC oil? If so, how? And, what its capacity to refill it?

I plan to replace the following things: coolant, LIM gaskets, SC gasket, SC coupler, needle bearings (if necessary), SC oil (if necessary), plugs, wires, fuel injector o-rings, valve cover gaskets, radiator hoses, accessory belt, SC belt, thermostat, by-pass elbow, throttle body gasket, and the PCV valve.

Did I miss anything that you guys would replace while I already in that deep?

1. NGK, Autolite, ACDelco are the preferred ones.
3. Dorman/Help! - 47065 at your local Auto Zone or Advance Auto Parts
5. Yes you should, along with the coupler, you will need gasket sealer to reassemble the nose to the rotor plate/supercharger. I believe it'* 2 bottles for the M90.

What NGK plugs in particular? I want to stay with NGK, if possible.

Oh ya, for wires, I already have a new set of AC Delcos.

TR55 are the correct ones. Gap @ .060

Something to consider on the plugs is the Autolite'* have the end cap built in and the NGK'* frequently are screw on ends. This means the part where the wire hooks can be loose and should be tightened before installation. Some have seen KR from these loosening.

Fllush before gaskets. Coolant flush takes me half to a full hour. Pull the draincock, open the radiator cap and let it all drain. Then flush into the rad cap area, overflow, pull the heater hoses..and upper radiator hose at the tstat housing. Flush it every way possible. Then fill or keep the supply going with the hoses hooked back up and start the car and flush while it'* circulating. After a minute or two.. turn the car off and flush every which way again. Repeat until you see absolutly no color for quite a while. Either Prestone LL or Anycolor.. to replace.

Leave the needle bearings on the SC. With your current mileage they should be fine for some time.

SC oil .. yes.. pump it out with an old spray bottle or a syringe/turkey baster (not the one you plan to use for T'Day) and refill with 2 bottles of oil or to the bottom of the threads at the plug hole.

Saw that you plan a coupler. You should still remove the oil ahead of time as it would make a mess on the engine. Ensure you get the GM red gasket maker. Small tube is all you will need.

On the valve cover gaskets..get the grommets as well. (Usually sold seperately).

for all o rings. Both fuel and coolant elbow. Lube them with lightly vasoline or grease to ensure reassembly goes smoothly. Not lubricating them could lead to a nick or pinched ring.

Another side note: If the engine is slightly dirty.. clean it super well before starting. This will help ensure that none of this muck gets into the engine as you take pieces off. And don't try to clean the inlet of the SC or any part of it beyond the gasket surfaces. (See my rotor coating peeling thread )

What is the appropriate AutoLite to use with no mods? You make a very good point about the screw-on caps on the NGKs. That was the one thing I never cared for about the TR55s I used to run in the 99 SE.

Do you recommend the use of one of those Prestone flush kits? I think you have to cut into the heater core hoses to make it work. If not, is what you're suggesting to use a conventional garden spray nozzle and blast water into each of those passages?

Torque values. Is it safe to use the torque values listed in my Chiltons for the Bonneville? The manual does cover VIN 1.

I think it'* an autolite 605, check with the parts counter though.

No nozzle.. open hose and let it rip. You want maximum volume, not necessarily pressure. I don't personally use a flush kit. Because it doesn't necessarily get all the parts that I am suggesting, and while the cost is low..it has a cost. Unhooking clamps still free.

Torque values can be found in your Chiltons, Techinfo and many threads here. Searching on me with "SC Lower" will bring up a thread I did couple years back with part numbers, tools and I think torque specs also.

Welp, I'm almost done with this project. I've severly taken my time, but I think it'll pay off. Pics to come in the AM.

However, in the mean time, I need a question answered. There'* one vacuum line that I can't determine where it goes. Directly under the SC there'* a rubber T. The front tube on front side of the SC goes to a fitting on the front of the engine. The back one (the long one with a bend) goes to a mysterious place! Can anyone bail me out, please? Sorry...no pics of that particular tubing. Anyone with a SC should know what I'm talking about.

Mark, check the Gearhead photobucket account. There'* some good detailed pics in the S2 L67 section.

Mark, the line from the "T" under the supercharger that goes back toward the firewall connects to the MAP sensor.