Polyurethane mounts for street car?

[DirtyWhite77]

Pulling the motor out of my 1977 trans am for various small fixes. While it’s out I’m gonna pull the front subframe  and replace body mounts, control arm bushings, and sway bar bushings with new polyurethane. I’ve read on other forums that poly bushing in control arms on 1st and 2nd gen cars can cause the control arms to not flex right since they are designed for rubber. I also have concerns about squeaking when new or old. I’m not terribly concerned with ride quality, although if that’s going to be effected much Id like to know. I just want them to last, not throw anything off, or squeak to high heaven.

I’ve already removed the rear axle and replaced all the rear bushings with rubber. 6 moths of sitting and driving around the neighborhood they are squeaking and the inner sleeves have eaten the rubber inside the bushings. I’ll go back redo those with poly bushings if they are a good idea.

[Wallington]

Poly in any control arms, it's a twisting force rather than compression. Designed for the track where road surfaces are smooth and don't vary much. The cons far outweigh the pros for street use. But body mounts and sway bars etc, good to go, they allow the suspension to do its work. Engine/driveline mounts depend on the owner,  can make for more vibrations for some, others like the feeling everything is tied together.

[81Blackbird]

I had the poly on the sway bars and leaf springs.  Squeaked all the time.  Since I didn't drive it a lot I put up with it.  Moly lube didn't help.  Replaced them years later.  They did work well
suspension wise though.

[Wallington]

Any poly sway bar mounts I've purchased lately have had that felt strand lining and no lube required. Not sure how they last long term but have never made a noise, have on daily driver and weekender. I still have the greasible mounts with grooves on Firebird.

Here's a few pics and variations, the brands don't matter but show what's  around.

https://www.suspension.com/blog/prothane-vs-whiteline-which-brand-should-you-to-choose/

[Jeremy]

I've tried Poly in all of the spots through the years.  The only place I have poly left is on the sway bars.

I did not like them at all in the leaf springs and went back to rubber.

I did not like them in the front control arms and went to greaseable solids on the uppers and rubber on the lowers.

I had them on the body mounts and went solid with SFC's bolted and welded in.  I would make you a good deal on the body mounts if you like.

They squeaked too much in control arms and made the rear suspension noticeably harsh.

As for the body mounts they were slightly more noisy than rubber and not as stiff as solids.  I wanted the most structure help with T-tops so I went to solids.  As for NHV with the solid body mounts, it depends on other things too me.  With the new motor, Mass loaded vinyl(MLV) and a good stereo its as nice as a new car inside.  With the rougher motor and the lack of MLV it seemed to transmit more of the roughness from the motor.

My son has a 79 Camaro hard top with Solid uppers on front and rubber on the lowers and in the leaf springs and rubber body mounts and his car has more noise inside than mine.  His isn't as well insulated as mine and I think the 305 is a little rougher than my motor but a fairly apples to apples comparison and I don't think body mounts are going to be a huge difference in NHV if everything else is running right.  In fact I think I have less rattles due to the more solid structure.
 

[Wallington]

Did you have subframe connectors at the time when poly mounts were squeaking? That seems odd unless still a fair amount of movement or flexing somewhere. One of the first mods I did 15 years ago was poly mounts, before any bushes or SFC's, worn-out jelly suspension, not a peep. Also a hard top.

[Jeremy]

Sorry for the confusion.  No squeaking with the body mounts.  I swapped to AL when I added the SFC's as the poly by themselves wasn't stiff enough for me.

Plenty of squeaking in the control arms though.

[Wallington]

Gotcha, that makes more sense!

[DirtyWhite77]

Thanks for the help guys. I’ve found a couple of places that sell rubber control arm and leaf mounts. The sway bars I’ll do poly, not sure about the body mounts right now. I have a 1979 ford truck I’ve replaced the rears with poly bushings years ago and they haven’t made any noticeable noise and they made the truck ride better than the clapped out rubber they replaced. I want a little bit more performance out of the firebird though.