Body bushing question?

Ok guys quick question to all you turbo gurus!
Looking to upgrade my body bushing and bolts. Looking at summit and Kirban a bushings. My car is all stock no significant upgrades other than your rear braces and front braces. Drive only a few hundred miles a year. Do not race it just your average GN with 36 k on it.
Which ones would anyone recommend? Is one better over the other? Or are they the same s**t? Part number for the summit is 3.4141G and Kirban a pn# 7305.
Any input is appreciated?


My question is not the ride, the material I get is different I understand the different. Poly vs rubber. Kirban set is 250 and the shipping he charges is almost a arm and a leg. Summit is 159 plus free shipping.
So my question does Kirban come with some extra bushings the summit doesn’t ?
ooh that is the entire set I was just looking at the set of six that is easy
that compete one requires the whole body to be removed from frame
I would stick with kirban though but anyways let us know how it turns out
If you are hell bent on a bone-stock concourse accurate car, the Kirban set is what you want.

Everybody else should get the polyurethane sets. Doesn't matter which one, they're all nearly exactly the same.
ooh that is the entire set I was just looking at the set of six that is easy
that compete one requires the whole body to be removed from frame
I would stick with kirban though but anyways let us know how it turns out
The whole body does not need to be removed. You do one side at a time with a jack and a 4x4 and your all set. I did mine on the floor of my garage. Just watch out for your fillers

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Yes the poly is a little harsher from what I have read in past post. Don’t know how much harder because I haven’t committed as of yet to what bushings. I would gues you would notice it when you first jump i. Your ride but after wards you will forget about it and not even remember the softer ride. That is my guess.
I have the Energy Suspension 3.4141G kit and it is very nice. Comes complete with all the sleeves and washers, fits perfect. Want to get the kit even cheaper than Summit? Go to Rock Auto

and I agree, shipping is ridiculous with some of these vendors
What kind of ride difference is there between poly and rubber? I've heard the poly is a "harder" ride. If so how much harder?
The poly is going to rigidly tie the frame to the floorpan and effectively turn the car into a unibody. The body stiffness will increase dramatically.

This does not affect the ride. That's a function of your suspension bushings, shocks, springs, and tires. If your bushings are shot, you're going to feel it, because the body bushings won't be soaking up the slop anymore.
@Cyrus72, I did a ton of research on this topic for my garage queen. re-read what Andrew wrote in posts 6 and's my input...

OE rubber body cushions will crush, crack, dry rot, etc. over time and will need replacement in another 15 years or so - depending how the car is garaged/stored (in the dry Arizona heat, salt air and high humidity of Southern Florida, etc). Doing a search I'm sure you can find the threads with pics of misshaped, crushed, cracked OE body cushions removed.

there are different durometer hardness values for the various brands of poly body cushions. Energy suspension is the highest durometer (hardness). Prothane brand poly mounts have a durometer value in between the energy suspension and the OE rubber.

In this Summit link here, are the listings for Energy Suspension, Summit's house brand, and Prothane kits for our car. If you choose poly, get black ones as they have graphite impregnated in them unlike the red ones. At SEMA, the Prothane rep noted they are not making the private label kit for the Summit brand.

I choose the Prothane kit 7-132-BL....a poly not as hard as NRG, black in color with cad-yellow plated washers & sleeves containing all bushings 1-7.

Note that the poly kits all include positions 1 thru 7. the OE rubber kit from Kirban's, OPG, Classic Industries, etc. are only positions 2-7. you have to separately purchase upper and lower for position 1 - the radiator core support bushings, from Kirban's. Ever notice how the vertical gap between the door and fender can get smaller as you get closer to the ground? Besides our Buicks not having the best panel alignment, the uneven vertical door gap can be caused by old, compressed radiator support bushings in position 1, causing the front clip to sag.

If you choose poly body mounts like the Prothane kit, I have to suggest the following....

do not use poly motor mounts or poly trans mount with poly body mounts. there is too much vibration transferred to the dash using all poly mounts. Keep things quiet and install new OE rubber motor mounts and trans mount when needed. MOOG has good choices, buy from Rock Auto.

At some point you may redo your suspension bushings - front upper and lower control arms and rear upper and lower control arms.
the best choice for a stock street car are the Moog Problem solver bushing kits in the front (MOOG K6411 & K6421) and MOOG K6178 for the rear (all, upper + lower).

Federal Mogul currently has an inventory control/quality control issue with the K6421 kits. I wrote about this back in December. Kit was coming with only one random bushing and not the 4 cad plated units for both front lowers, both sides. Federal Mogul pulled all inventory of this kit and has to schedule production at the Mexico production facility.

check out this thread...

you'll need new bolts for the mounts.
Anthony P!! Give this man a beer! Wow amazed at the knowledge. Actually I shouldn’t this board if full of wonderful knowledge like this.
Thanks you so much for the sharing the information and your research.
Only going to do it once and I think I am going with the poly
Thanks again!
thanks for the post cyrus72 I will being doing my body bushings too I also saw the the frame washers on gbody parts might need them as well but I have been focusing on cosmetic things for a year now and have been forced to address mechanical issues now
so much to do so much too learn
Grass doctor indeed. All my focus has been on the looks of the queen. Now it’s time for the mechanical issues and or minor upgrades that are recommended on this forum. They weren’t lying that these cars are a money pit. But a fun one! And well worth it every time I take her for a cruise and I get thumbs up at every light.
What’s funny I add the number of thumbs up I get every time I take a cruise and divide it by the amount I spent that week or month on the car. And that’s how much it cost per thumbs up. Just a way to justify the money I spent. So the more thumbs up I get the cheaper the upgrade is. :LOL::p:p
hahaha thats awesome
my wife asks were you going , going to get my boost/ it sure does feel good getting the thumbs up when your out cruising that makes it all worth it , I just need to learn to ignore the jokers wanting to race but they just want to see her in action and I would too :cool:
You're welcome, cheers

maybe for continuity, I'll add a note about the stabilizer bar bushings and end links...stock OE bar is 1-1/4" bushings and links are really up to you. By default, for OE stuff, the conversations usually reverts to Moog as the OE supplier. Two points (recent) to ponder here:
1. not a fan of these new blue color bushings and link cushions that Moog is producing.
2. considering the recent Moog inventory/quality control issues with BOTH the K6421 Problems Solver kit and the K6177 OE rubber kit (new thread), have to ask or wonder how much more Federal Mogul & Moog parts are now crap?

MOOG 1-1/4" blue bushings are K6455 - lifetime warranty
AC Delco Pro 45G0652 are the same but BLACK in color - lifetime warranty. See pics on RockAuto
Energy Suspension poly, greasable bushings are nice - part # 9.5165G here on Summit. they look real nice on Byron's (@trick86) 86 T-Type he just sold underside pics - post #3

For both the Moog K6455 and Delco Pro 45G0652, you'll reuse the metal bushing housing - media blast & repaint or powder coat.

For the end links, I choose the Prothane set part # 19-412-BL continuing the theme with the cad-plated (or yellow zinc) hardware for the body mounts and the Problem Solver control arm bushings (front) I'll get one day when Federal Mogul gets their act together.