k member isolator bushings

NoCar340

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No. I suggest the aluminum, if you don't mind paying the obscene amount of money they're now asking for them. $225 is out of hand for something that costs mere pennies to make. Aluminum is inexpensive, casting it is easy, and the tooling to make the molds for those isolators is neither complex nor costly. It was bad enough when they were $150, but at $225 I'm exploring other options. Poly is not one of them.
 

72Dodge

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Why? They are awfully hard. Seems like it would depend in intended use, but wouldn't poly be just fine for most applications?
 

72Dodge

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That said, I would have gone with aluminum too, if they were reasonably priced, or if I wanted to bother with making them myself,
 

NoCar340

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Why? They are awfully hard. Seems like it would depend in intended use, but wouldn't poly be just fine for most applications?
The poly isolators hard, but they're not solid. They have some flex, and they will give. Yes, they're fine for 99% of applications but no, they're not as effective as the aluminum. With the aluminum (and the earlier Mopar/DC iron isolators), the frame rails are tied solidly together as close as you're going to get to the A/E/pre-'73 B-body setup. Ultimate handling, and high-torque applications pretty much require the solid isolators. I would consider them a must for an RB engine or a well-built 4" stroke small-block--particularly with a manual transmission.
 

72Dodge

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Fair enough... For those few who really need it, go aluminum. If I ever install a big block, I may also. I'd say they have to be a far cry superior to the stock rubber mush though, that's the way I see it.
 

brotherGood

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But, I'd be ok using poly for a cruiser/occasional strip & autocross "fun" car..right? When it's done, it may have a 360..but that's about as extreme as I'll go
 

NoCar340

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Yeah, poly would be fine unless you get truly silly with the 360 and back it up with either a 4-speed or something with a high-stall converter (I mean high, not 3,200RPM :icon_biggrin: ) and a transbrake. You'll give up a little on the autocross course, for sure, but if you were taking autocross really seriously you wouldn't be using an FMJ car in the first place!
 

MiradaMegacab

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Perhaps a visit to a local metal supply house can get you some small scraps of 6061 bar stock. Make your own aluminum pieces........

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76volareman

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bought and installed the poly bushings from summit racing. designed for a "b" body but installed easy enough. fronts are easy to change by loosening bolts and dropping member down but rear bushings i had to take the upper ball joint loose, take the 4 upper control arm bracket bolts out and loosen the cross shaft to get the a arm up out of the way of the bolts. then take the shock loose at the bottom then loosen the member bolts in front and then the rears could come out. not that hard on a lift with a few screw jacks.
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brotherGood

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Yeah, poly would be fine unless you get truly silly with the 360 and back it up with either a 4-speed or something with a high-stall converter (I mean high, not 3,200RPM :icon_biggrin: ) and a transbrake. You'll give up a little on the autocross course, for sure, but if you were taking autocross really seriously you wouldn't be using an FMJ car in the first place!

Well, thanks for the advice. The autocross would be just for fun. It's more of a fun car anyway.
 

76volareman

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i felt a real difference in my volare with these poly bushings. Even with ok original bushings,it felt much better goinginto and out of turns now. it used to try to dart and squirm durning xorners but ok now.
 

BigWhip

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If the bushing is made out of aluminum, can the bushings be made thinner(1 inch thick) without any interference issues?

Michael
 

NoCar340

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I suppose it could if you don't mind fabbing a solution for your buggered steering-column & drivetrain geometry and a few different clearance problems (exhaust, hood, and possibly control arms). If you've got a column shift you'd likely have to rework that linkage, too. I guess the question would be why would you want to? If you want the front lower you could simply adjust the torsion bars.
 

tallboy

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I have a set of poly bushings for my '77 Aspen Wagon, but I haven't fitted them yet. I have a slantsix, so I don't worry about the total weight of the k-member. I agree with dodge72, if I had the added weight of a BB trying to move around, I would use aluminum or steel. I have also seen some DIY kits for casting your own poly mounts, that way you can tailor the hardness to your needs.
I have a complete set of poly mounts for the entire car, but I have been getting second thoughts about engine and gearbox mounts, regarding transmission of noise and vibrations by harder bushings. I addition to the k-member mounts, what I really look forward to, is to feel the effect of an added sway bar and poly mounts for the rear axle!

tallboy
 
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