another vote for ESPO. I have +1 springs on all my Darts - some of them 20 years old. They do settle in the first year and then more over time, so your best bet is a +1 or even a +2. Be sure to order 6 leaf springs - that's what all the 340 A bodies of your era came with. They come with the...
send a pm to Halifaxhops here on FABO - he's right there in PA. He does a great job of checking out, repairing (if needed) and recurving your distributor. Wait until you figure out what all you want to do and send him the details on the engine, gears, etc and how you want to use the car and he...
plus getting the edges cut to fit right under the sill plates! Next try doing it with a console with shifter in the middle!
PS: I do love that paint color!
Buy a house on tall stilts, not sure how to get your cars above the water, and be sure to take your snorkels. I was in Florida a few years ago and thought it would be cool to go to the highest point in the state, which turned out to be in a flat plot of woods next to a rural road side picnic area...
first thing I would do is put a dual plane 4bbl intake on it. With dual exhaust and 360 heads, that motor is just begging for it and the results will be significant.