Hokey ass brothers and sisters, I'm building a '40 Chevy sedan, and I'm mounting the leading end of the leaf springs inside the frame rails, as opposed to beneath them, to eliminate, or at least reduce, the need to use lowering blocks to lower the rear ride height. I think it may also improve handling. In any case, locating the attachment point inside the frame rails makes the springs much less parallel to each other. The difference between the width of the leading and trailing ends of the springs is 8 inches. If it matters, the springs and differential are from a '73 Nova. Anyone have experience doing this? Any negative effects? Positive effects? Innovative Rod Shop sells kits to do this so I'm thinking non-parallel is probably not an issue but I'd like the real-world expereince of guys and gals who have been there and done that. Thanks!
In the 20s Hudson/Essex mounted their rear springs with the rear splayed out wider than the front. The springs served as a stabilizer as well as suspension. Chevrolet also did this with their front quarter elliptics in the 20s. There isn't much that is new just that which is improved upon.
I put the rear axle & springs from a '69 camaro under my '49 fleetline, and they are non-parallel from the factory, narrower in the front than the rear. I found a good article on line regarding this, it is attached.
The non-parallel aspect is not an issue. However, the closer to the center of the car the springs are mounted (i.e. inside frame vs under or outside) the less they are able to resist body roll. So, net effect, I don't think handling will be improved. Just the opposite. But you can install a fairly stout anti-roll (aka 'stabilizer) bar to counteract that problem. Ray