I still keep 5 ads on Racing Junk all the time. Mostly parts I have bought and not used or some of my friends good parts they don't need. Mild success. I have 1 new engine and one rebuilt engine on now. I have had calls about details. Mostly guys looking for Procharger type grudge stuff.
I also keep ads on Craigs list for parts I don't want to ship. I sell some engine parts, carbs and engine oil on there too.
Right now I get more response on Facebook Marketplace. A few sales to Puerto Rico too. USPS flat rate boxes and USPS money orders work for there. Marketplace also lets you post on other buy and sell car/ racing groups. I am on 10 groups right now thru Marketplace.
All you can do is have good pictures, a detail description and be priced where a buyer will contact you instead of Jegs or Summit.