323 355 or 373 gears??

I like blueprint engines, I'm trying to decide between a 540" or a 598" shortblock for my opel.
My tires on my car with the 4.10s is a 275/60x15 on a 69 runner with a factory 4.10 dana. I considered changing the gear, but I thought going down to only 3.54 wouldn't be worth the cost and effort (especially since my friend/rear end specialist passed awayl). Now with 3.23 available , I'm rethinking the change.
On your tires, that vintage barracuda has a fairly open rear wheelwell, but it is not very long. A 28" tall tire, like a 275x60, might fit, but i doubt it, not without modifying the opening (done frequently). I think the shorter tire will fit, but be closer to the outside fender. On either one, wheel backspace will have to be right! You are aware that your barracuda comes with a tiny bolt pattern wheel, and there is not a lot of choices, right?
Edit, brainfart. If you swap to the dana you will have the lbp automatically.