What walbro will work in place of 340 or 682

[dufrain]

I am looking to replace a one screw wt 682 with a 2 screw.I have a wt 340 on an older machine ,it is a 2 screw ,but I cant find one of those either.Are there any charts to show what other model walbros will fit .Im just looking for a used one,I dont mind to rebuild it.Thanx guys