Since installing my new 427” LS engine I have had some problems with my rear leaf springs wrapping and the car squatting under hard acceleration in the low gears. The leaf’s wrapped enough that I could feel a very slight drive-line vibration. I had to use wedges to change the pinion angle by 3 more degrees to eliminate the vibration problem. The car still handled good with the Hotchkis multi-leafs and rear sway bar set up… but I didn’t like the squat and the wrap.
My plan was to switch out the leaf springs and rear sway bar set up with a Quadra-link this winter. After getting some input from a couple guys on here, I decided to try the Global West Cat-5 road race leafs as a next step, rather than go to a Quadra-link.
The GW leafs have spherical bearing mounts on both ends, and a full floating, heavy duty shackle mount. When I called Global West they said the Cat-5 leafs were rated to handle up to 700HP. I bought the Cat-5’s with the reverse eye mount, so I could get the car as low as possible and not have to use a large spacer between the leaf and axle.
Cat-5 with reverse eye in the back and Hotchkis multi-leaf in front
The GW leafs have a spherical bearing mount at both ends vs a rubber bushing.
These GW springs were expensive, but well made
Close up of the spherical bearing and spacer
Spherical bearing with spacer removed
Here is a shot of the shackle and bushing set up with built in grease fitting
The blue anodized aluminum sleeve presses into the rear sub frame, and the white delrin bushing slides inside. The bushing fits very precise and does not allow for lateral movement of the shackle and leaf spring.
Installing the leaf in the car
Here is a shot of the front spring mount with the reverse eye set up on the leaf spring
I used a 3/4" thick spacer with a 3 degree angle between the leaf spring and axle to set the pinion angle
Cat-5 leafs installed with wedge spacer
Spring swap completed!
I have been driving the car with the new leafs for a couple of weeks now. Major improvement... the car does not squat on acceleration... hooks up much better... and feels way more stable in corners. I will be doing another track day in two weeks and I can't wait to try out the new set up.
Thanks again on the good advice guys.
Brian Hobaugh SCCA National Tour June 2014
First Hemi 'Cuda Convertible Ever Built
Short clips: Goodguys Pleasanton autocross and pit videos
We spent some time talking to the mechanic and driver of this nice 1967 Z28.
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