I'm 100% sure that particular combination will fit my '71 Dart with it's 73+ BBP disks and A-body 8 3/4 with stock springs and BBP axles. It's actually a fairly conservative combination on my car, it should leave plenty of room. Those are the specs of the rims and tires I plan to run on my '71 Dart, unless I talk myself into 255/45/17's.
That said, it's not unusual to see suspension and body tolerances that are off by a 1/4" or more on these cars, and based on the measurements I've seen from people here the pre-70 Darts tend to have a little less room in the back (in general) than the 70+ cars. The pre-70 cars seem to end up on the small end of the tolerance range more often than the later ones do.
Without knowing the measurements on your car in particular I can't say for sure they'd fit. I do know of pre-70 Darts running tires that size without any issues at all and room to spare. I also have seen a couple on this board that had clearance issues with tires that size in the back. Only way to be certain is to measure YOUR car, figure out what the distance is from the wheel mounting surface to the springs and the quarters and do the math. You may find your car isn't even the same from one side to the other, it's not uncommon.
50 series tires for a 17" rim are an option, but it depends on the size. 245/50/17's are pretty easy to find, but that's a 26.7" tall tire so they won't easily fit on the front, only the back. And when you get into 50 series tires you see a lot more options for light trucks and vans, you don't see as many performance tires. 245/45/17 is a popular size so there's good performance tire options with good tread compounds available, and it's a 25.6" tall tire which works well in the front and is a decent height for the back as well. It's a good size to run front and rear if you want to run the same size on all 4 corners.
