Proper Exhaust Diameter fo a 4bbl 225?

Id see how they take care of it before I decide whether to stick with them. Did they do the actual rebuild? Machine work too? Or did they just remove/replace and someone else did teardown and build up, and the shop where it's at just reinstalled it?
Depending on how many "3rd hands" we're involved, warranty could be a cluster.
Another reason why I do as much of my own work as humanity possible. And stop by the machine shop to check on progress often til I get my parts back into my own hands. Cuts down on blaming "they" or them" and the passing of the buck.