FMJ body rear spring ISO-Clamp

[Bill55AZ]

Does anyone know if a harder substitute for the rubber cushions around the rear springs is sold anywhere? Or has anyone made something themselves that worked? I wonder if machined aluminum blocks could be inserted?

[Tarrbabe]

I'm not sure who would make them but several years ago I read somewhere that one of the mfg. of the poly bushings made them. I also read about a guy that machined some out alum. and they worked well but transfered a lot of vibration to the inside.

[goldduster]

Isn't the isoclamp how the rear axle attaches to the springs? How would that transferr harmonics into the car when there are still rubber bushings on each end of the spring? All of the earlier cars just have them mounted directly to the spring without rubber isolators.

[Bill55AZ]

Good point, GoldDuster. For a daily driver, I would leave them in. But for one I am building, I want moderately stiffer everything in the back since there will be around 300 horsepower pushing it where there was only 130 before. I am looking into ESPO springs with the 2" extra arch unless someone out there has a better idea.

[Tarrbabe]

Sorry, I mis-understood your question. The ISO clamp can be changed out with an older setup (Duster set should work) and the firmness and feel would not be greatly changed. I was speaking of changing out the clamp and also the front and rear eye bushings. The oval front was what I was mainly thinking of as they allow the springs too much movement for true performance.

[Bill55AZ]

Makes sense, I might go poly (or whatever it is) on the bushings, but certainly nothing harder than that....and the springs are so old that they probably need replaced as well.