I have a 1965 Chevy Impala convertible that I am trying to find front & rear springs for.
I purchased a set of springs that (with the help of all the other stuff) make the car ride like a lumber wagon, I have been told that the front spring rate is 403.9 and the rear is 243.
The front has no travel at all and seems much to heavy, the car also sits high in the front but OK in the rear.
My car has the following; The car was originally a 283, power glide, air car, power steering, manual brakes. It now is a 502 Ram Jet, 700R4 auto, with vintage air, 4 wheel disc power brakes, griffin aluminum radiator & electric fan.
I am sure this has changed the front weight substantially. Urethane bushings for the body mounts, all suspensions bushings, the sway bar bushings and shock bushings. The suspension is stock original stuff, upper, lower control arms etc. KYB gas charged shocks, front & rear 1 1/8″ front sway bar, it originally was a 11/16″ bar 1″ rear sway bar, it originally had no bar 17″ Nitto NT450 tires, 255/50 front, 275/50 rear on American wheels I would like to have a firm but comfortable ride, a stock to slightly lower maybe 1″) height.
I know the ride is a subjective thing, but if it were of a stock feel that would be OK. I can weigh the car if necessary, getting a front wheel, rear wheel & total weight. Any help would be greatly appreciated.
Sorry for the long delay is responding to your email. I was luckily (?) and was on vacation in an area that had real spotty cell phone service and no email. I am in town just long enough to pack my belongings and go back. OH, I was just told I can’t leave anymore. Oh well. OK, your ride, sounds sweet. Now lets make it sweeter.
The 502 weighs the same as all big blocks, but the other changes made in the front, stock ac out, Griffin radiator, etc has probably brought you back closer to small block weight.
The big block front springs have a rate of 403 lbs which is what you say you have.
The KYB gas shocks and the bigger sway bar and urethane bushings are not helping the front suspension. Gas shocks require more force (weight) to compress than the old reliable hydraulic shocks. When this additional force is added to the springs the ride becomes stiffer. Carrera still offer a limited line of gas shocks, but not for your ride. Both QA1 and Edelbrock shocks are gas but they have a much lighter charge than anyone else’s and provide a very nice ride. Plus the QA1 offer a 12 way or for the real techno owners, 576 way adjustability. While the Edelbrock’s adjust automatically.
Just replacing the old rubber sway bar bushings with urethane is equal to increasing the bar size, but when doing both the bar size upgrade and going with urethane bushings you may have reached the overkill zone. And unless you want to feel the mint mark on a dime, keep the rest of the suspension bushings rubber.
Now let’s get you riding better. First, change the front springs back to small block springs, this will soften the ride plus get you down about 1.1 Inches.
Change the shocks to QA1 or Edelbrock’s and go back to rubber sway bar bushings. The rear springs sound fine and you are happy with it, so leave it alone.
We do not carry swaybar bushings but they should be available at your local autoparts store.