Correct me if I am wrong but aren't the E body leaf springs at an angle? Closer in at the front than the rear. That stands out in my mind for some reason.
Yup, E-body springs do have a little angle on them and are narrower at the front. But the leaf spring perches themselves are not angled, they're straight on the axle housing. Although it wouldn't matter, they're also 46" center-center so they'd have to be moved to go under an A-body anyway.