Boy, never dreamed this thread would go where its gone
...no use going into a lot of detail right now but insteadk of paying that high price for an "oversized rod" drop by the hardware store, or Lowes where I got mine, and for less than $4 bucks you can get a 3ft stick of 5/16, which is what mine is, and make your own. Press the old one out, put the new one in and cut a slot for the spring with a dremel cut off wheel or some other. There is also enough room in the flapper to go a little oversize on the rod and still work nicely in flapper.
.....you can drill the manifold to what size you need. But check close for bushings. Either way.....its a nice satisfying project regardless of which, or what, you do to yours. I'll keep mine original....or as Cletis would say "restored to original".
