They are a factory 15x7 rim, I didn't want to mess around with the math on new rims so went with what I know to work. First guess was 4-3/8". I'll look it up and post it here.
A couple weeks ago I finally picked up a carb tuning kit for the Edelbrock as it has always run a bit rich - you can smell it. I used the 8% leaner chart calcs and swapped out the main rods and the secondary jets. Man that made a difference! Smoother power and a bit more of it, plus the smell of unburnt gas is gone. If that didn't work I would have bought a air fuel gauge and fine tuned it more, but looks like I've got it settled in. The car seems very happy now and I love cruising it around even more - between the new tires and the tune I think I'm set for a fun summer!
Getting ready for a ferry ride across Lake Michigan and the upper part of the Circle Tour. Can't wait!