Tire question. Just simple bottom line

E70-14 bias or P205/70R14 in p metric sizing.. this would be stock sizing on 1972 dart with a 340.

You asked for max sizing so a F60-14 should fit the front and up to a p245/60R14 rear should also fit. Although the 245/60R14 might be a touch wide for a stock 5.5”w rallye.

Seeing as you want to run the same size all around I would say max sizing is F60-14 or
P215-225/60R14

hope it helps