Leaf Spring Modifcation with Coil Over Shocks©
Leaf Spring Modification© by Dean Oshiro
Not everybody can afford the latest and great. When I was building cars this trick worked very well for our customers on a budget. 1994 to 2010© Dean Oshiro
Leaf Spring Modifications: This is a simple way to obtain better suspension out of you stock leaf suspension. I have done this many times when a customer is on a budget. This allows you to keep the stock suspension or modify them slightly. Of course if you can afford a 4 Link gives you to best performance when engineered and installed properly. Below I have outlined two methods moving the spring or not moving the springs.
Coil Over Shocks: First of all we advise using the best coil overs on the market, QA1's. All the other brands are "want-a-be's". QA1's are what everybody copies. So they are coping the best. QA1's are adjust the compression and rebound simultaneously. All other shocks adjust either the rebound or compression.
Coil Over Installation: Remove all the leafs but the two (2) main leafs. Then run a set of our QA1's with 95-120 pound coil springs the softer spring allows for right and left ride height adjustment. For drag racing applications we can even preload the right side with a 25-60 pound heaver spring. The QA1 shock body can also be adjusted by turning the adjustment up. Installation should be done eyelet to eylet and not eyelet to stud mount. In some cases you will need to add a upper cross member for the shock mount and/or a lower shock mount to be welded to your rear end housing. The lower shock mounts are available almost everywhere.
I have found for street application it is best to mount the shocks at 60 degrees this puts the shock at the hypotenuse of the triangle. Hypotenuse? The longest length. By doing so allows greater up and down travel than a 90 degree mount. The angle become critical on lowered cars. See Ride Height.
Moving Leaf Springs: In most cases the easy way to relocate the leaf spring is just simply move the left side brackets to the inside of the right side rails and the oposite on the right side. This will move your springs inside the frame rails and allowing you 3-5 inches of additional tire. On springs mounted at an angle mount the front bracket first, then locate the rear where the angle allows.
Traction: Caltracs have always worked the best for leaf spring set-ups. For under $400 how can you go wrong.
