[flatrod]

Thanks for all the good info. This is what we have, 56 TBird with a 55 carb and intake. It wasn't working with a later dist. I have a 56 dual vacuum Bird dist, put it in with the one side to the original 55 vacuum port and the other to a vacuum source at the front of the manifold, manifold vacuum. Looked to me the same as using a 56 carb. Still does not seem to work right. It may have a bad vacuum can on one side or the other. Its a friends car, when it comes back to me, I will test it, but I think he will go with a 57 dist and run it without the vacuum advance part.