I'm looking for opinions on a proposed design to allow a Proffit's rear 4-link design to keep the full length springs that were sent with the kit. It involves cutting into and modifying the frame substantially so I want to be sure of what I'm doing before committing. Cutting the springs so that they fit under the frame means that at least two active coils would be lost (meaning I could carry considerably less load) as well as changing the spring rate and ride characteristics. Before anyone says 'why in the *#$%#^ would you do that, it's not worth it, just cut the spring'...this is a project car and I'd like to do something different. It's an interesting change and I'm having fun with it...enough said, this is the way I want it. I also realize that I would need to raise the rear floor on the body tub to make this work. I have parts modeled up in AutoCAD and was able to get some screenshots of what I am thinking of: - The first two are of the uncut spring compressed to ride height as it sits under the stock frame. As you can see, with the way the upper spring buckets would sit under the frame, I'd lose at least two active coils. - The next shot shows the proposed cut into the frame to accomodate the full length spring, along with an added rail on top (blue) and a 1/4" thick plate for the upper spring bucket (also blue). Some of new structure that reinforces the area isn't shown in this shot but is shown in the next three shots. The rail on top of the stock frame would be 3/16" and fully boxed. - The fourth screenshot shows some ribs extending lower than the upper spring bucket base plate to carry the load around it. - Shot 5 is from underneath showing the upper spring bucket recessed into the frame. - Shot 6 shows the fully built up modification, with the added parts in different colors for clarity. - Finally shot 7 shows clearances for the rear tire and shock absorber. The rear tire is at the stock location and is a little close but I was going to add wheel spacers anyway. What is modeled up is a 35x12.5R16. So...anything I'm forgetting? Any pitfalls / things to be aware of when altering the chassis like this, like fatigue cracking in the years to come? It will be much stronger than stock. Thanks.