Since I have to do some work on my front end and pay for an alignment anyway, I thought I'd take this opportunity to replace the rubber K-frame isolators on my '78.

Firm Feel has the aluminum copies of the old Chrysler offering that are probably the best option.

http://www.firmfeel.com/b_body_late_mopar_sub_frame_isolators.html

However, for less than 1/4 the price, these polyurethane mounts are available.

https://www.summitracing.com/parts/ptp-4-101-bl

My question: Will the difference in performance be night-and-day, or will both be a marked improvement over stock with little difference between the two? I will spend the $250 if the difference is great, but I'd hate to if I'd never notice the difference.

One last question: Does anyone besides Firm Feel make metal copies of the old Chrysler solid metal bushings?

Thanks.

The solid K frame isolators are worth the money.
Speaking from experience driving and riding in my Buddy's 74 Charger.
Installation and fitment is bang on.
Handling is precise,predictable and firm.

So good to the point I will be doing the same to my 73 Satellite wagon.
My original isolators are petrified and the car handles like a wet noodle.

I didn't feel any difference going from shot out stock bushings to the polyurethanes. Later I went and made my own out of steel and welded them to the k-frame.

I would be interested in knowing how thick the Aluminum biscuits are above and below the K frame.

Otherwise known as info to fab my own.

I went solid in my wagon.

I think how noticeable the change will be depends on the model car.

For example, '73 B bodies that came from the factory with a big block have a huge opening in the inner front fender apron, where as the small block cars don't which offers more support. As such, you may not notice much of a difference on a small block car.

My wagon is a factory big block car. Where I noticed the biggest difference was on rough or washboard roads. The front end didn't dance around as much, felt more planted.

It's kinda like adding subframe connectors to the front of your car because you're tying everything together.

However, there are some that insist going solid makes the ride much too harsh. Me, I didn't notice that much of a difference in normal day to day driving. To me it felt no different than a '72 back B-body.

If cushyness is that much of a factor, sell the B and buy an Imperial.

Just my

Look closely at this pic on FF's website. The spacer is just between the K and the frame. A large washer is used 'below' the K.

Thanks to everyone for taking the time to reply. I really appreciate it.

I begrudgingly decided to spend the $250 for metal bushings (do it once, do it right). I'm also going to pick up Bilstein shocks for the front while I'm ordering from Firm Feel.

id be interested in the dimensions as well.

That washer is really all they use? That lip on the metal bushing and a washer sure isn't much to keep the bushing inside the k-frame.

Do it once,do it right...
Make sure you match them with the cross member kit as well

http://www.firmfeel.com/b_body_late_mopar_cross_member_mounts.html

ive installed the poly ones before and they have a male and female side so when assembled they stay tight,

these should be fine, looks like the washer is bigger than the shoulder and should keep the bushing in place.

Thanks 68Cbarge, I had forgotten that that the late B-body's t-bar crossmember also suffers from rubber isolation. I will get these as well.

I put energy suspension poly K frame mounts in my 74 charger was a small block car now has a big block in it. the poly ones I have are solid as a rock no deflection at all. Made night and day difference and car still has the small block T bars. very happy with them

I used the old MP kit in my wagon, and it's the same way. 20K miles of crappy Houston roads and never an issue.

Another free mod I did on those was remove the isolated torsion bar crossmember, cut out the torsion bar sockets and weld them into the frame. Converts it back to how the 72 and prior cars were. Also had to change to the older (shorter) torsion bars but wanted an upgrade from my stock SB bars anyway.

That's a good new for me! The rubber new repro pieces being made now are not affordable to me at this moment.