Lower ball joint question.

4.10s are just what a 904/City Slanty needs! You won't be sorry. You'll be really close to spinning A pair of those tall-boy tires. You said 275/60-15s right? Well as it happens those are about 28 tall and compared to the factory tires they will perform like 3.73s
How do I figure that?
Well 28s will reduce your 4.10s to 4.1x12/14= to a corrected for size 3.51, to a 24" tire
and the factory 25.5 tall tires will reduce a 3.73 to ; 3.73 x 12/12.75=3.51 corrected to 24"

To spin those 28s, your engine will need about 180 ftlbs out the axles, maybe 200 out the crank, so put a TC on your shopping list I guess.

235s are comfortable on 7.5" to 8" rims and the Coopers will last nearly forever if you keep an eye on the pressure and alignment; mine are at 29psi. However, they go hard after the first summer, just like the BFGs; so when you get back into the car, the following spring, keep that in mind; they won't hold in the corners like they used to. But 4-wheel slides are fun too............... right up until you curb it.