This is the size it called for my dart except I got a thicker 4 core.
Which ended up being so thick I couldn't use the clutch fan setup anymore.
Which was ok with me and I installed two fans in front of the radiator for a cleaner look.
As far as sticking a b-body radiator in your a body a tape measure or test fit will tell
The new radiator actually sat a little lower than the original so it had extra hood clearance