mounting a rear spring question

im builng a lakes modified roadster pickup. my question is the rear transverse spring off a model a. factory is bolted with the u clamps at angle to follow the curve of the crossmember and spring but everyone bolts them flat in the middle on a flat perch. does that make them bind since your bolting the center flat instead of following the curve. id say that also applies the same with the suicide perch. please enlighten me as this is a big decision in the design.

 

Your description was challenging to understand! I have only used maybe 2 dozen original model A rear cross members & springs in early Ford chassis projects, I always use the original U bolts as Henry designed. The cross members when used in 32 & 34 frames must be rolled down on the front edge some so that the spring, when attached to your radius rods does not go into bind making the spring compliant, from memory the cross member sits aprox 1/4" from the chassis flange at the front top area, hope that's muddy enough for you! Wayne

 

Unless you have a good reason for moving away from an original cross member I'd suggest sticking with original.

 

this is how i want to do it, but it bolts the center flat on a curved spring.



this is normal, u bolts at an angle natural to spring curve.

 

If you want it to look like the orange modified, but are worried about the curve, build your own mount with the correct curve.

 

I worked on that modified and the narrow mount makes for a lighter spring rate, the wider the mounting the shorter the effective spring and the higher the rate. We took several leaves out to help the ride too.
Keep it narrow, it'll look better too, not bulky.
IMO.

 

A couple of pictures of my rear perch. Does not show it very well but it is curved to match the spring.