If you are looking for functional replacement O'Rielly and Autozone are ok

If you are looking for cosmetically/appearance/NOS-ish replacement, Classic Industries and NAPA.

With NAPA, O'Rielly and Autozone make sure to bring the old.
All three have web sites with some times accurate pictures.

For my MC I used an in-correct one from O'Rielly but it had the
easy to use in-correct (I think)side bleeder screws