If any actual damage did occur and I agree with Jester it simply sounds still lean, then suspect valve springs that may have lost their temper.

I have no idea if this applies because I do not know if your installation is cowled but many, many folks have more problems simply because of the refusal to let enoungh air in especially even more air out. This of course requires cutting of the cowls and so many refuse to do this.

Just a few thoughts

John