Worth it is an opinion, depends on if you plan on doing more mods in the future. Why not use the 74-76 360 A-Body manifolds? They are much cheaper and flow pretty well...
Thank you. Will those fit without mods? Work with power steering? Very true, "worth it" is subjective. My plans are a 375/400 hp motor max. I'm all mixed up on the casting numbers, just don't want to order the wrong ones.