8.25 Suregrip rear end for 73 Valiant

That's the plan with the motor mild 318 also I need better gearing otherwise the performance part of the engine is pointless with highway gears. I like to have all my ducks in a row before I start something. Seeing how I can't find a rear yet after my constant searching, I do not want to one day break the 7 1/4 and then be stuck searching for a rear and my car be down until I have one.
It is possible that a sure grip out of a Jeep Cherokee or a Dodge Dakota 8.25 will fit,, so perhaps check out the local pull a parts,, but I may be completely wrong so check that out first.