A tank circuit is 2 components put in series, it's not exactly a difficult thing to do
All you need is a large capacitor, something like 35v 22000uF (microfarads) and a high current diode with low forward voltage drop (60A ~45v).
search on this forum, there are some part numbers listed.
Perhaps someone can post a link to a place where you can order them online? I know that there are quite a few places.