Low RPM stumble

"Recurved" is a suspect for idle problems also.
Do you know what springs were used, and if the total timing was limited in it?

I'm not too sure what exactly he did to it (good friends with the shop) he told me to try it out and if it didn't work well to bring it back so He can crush it lol. He said it was the most frustrating one he has ever done because somebody previously meddled with it.