I see the “S” which means LSD. Can’t see how many teeth are on the ring gear so can’t make out the ratio. My guess would be a 3.64. It could also be a 3.45 but that only came on the 2800CS and early CSL’s. Both ratios have an 11 tooth pinion gear but and you have late diff axle flanges with nuts on the backside. The 3.0CS came with a 3.64.
It’s really hard to tell with the crossmember in the way, but based on the aluminum near the bolt pattern the trans appears to be overdrive. If you snapped a picture at a slightly better angle or showed the tail housing it would be more apparent.