No scrap yards on my island and shipping from the mainland is very expensive. Please don't recommend a bigger unit, right now that is not really what i want to do. Hope someone can point out the strongest gear set.

 

While not having hands on experience with the 7.25 Chysler axle other than removing for a swap. I do have experience with the Ford 8" and 7.5". From what I have seen if I was looking for strength I would go with a 3.25 gear for performance gear based on the pinion size a ring gear thickness but the pinion bearing size is probably it's weak link.
I hope this is what you are looking for.

 

Thank you for the reply. A 3.55 is stronger than a 4.10? Because the pinion is bigger?

 

The pinion gear diameter is larger on a 3.55 than it is on a 4.10, it is on every gear set no matter what axle. The problem is problem is the parts are getting tiny on a 7.25 axle.

 

Thank you for the help.