I'm building a 31 Ford coupe street gasser and I was wondering can you use a model a axle on it with later spindles, new spring, and kingpins?
Sure, just be sure the king pins match the spindles. The so called round back ‘37-‘41 spindles use a k/p that is 1/2” shorter that the ‘42-‘48 square back spindles. Also be aware that there are shorter springs for some aftermarket dropped axles that are narrower. I realize you won’t be using a dropped axle on your “gasser”, just be sure to get the proper spring length.