In the past I've swapped steel to aluminum oil pans on both H/C and W body cars. Recently I almost suggested to a W guy that he buy an H/C pan by mistake. The mount under the harmonic balancer on the W body prohibits this and vice versa on the H/C body. The oil filter adapter is important depending on the body as is the oil pick up tube. Be sure to have the correct ones.
Here are the differences in picture form to help you guys make the right choices if you choose this "nice to have" mod.
W body pan with mount provision.
H body pan