6.7 IRS vs 7.5 questions

[SynthOkami]

Hey all, I had a couple questions about GT-S/IRS differentials.

I have an 84 GT-S, with an IRS 6.7 T382 rear end, and an 85 GT-S with an IRS 7.5 F312 rear end. I enjoy the 3.91 gearing of the F series more than the T series 3.42 gearing. I've also been told that T series diffs don't hold up to abuse like drifting as well as an F series. I have a F series 4.10 LSD from an automatic MA61, that I BELIEVE is a F293 if I'm not off. I wanted to swap that 4.10  into my 85, and put it's 3.91 into my 84.

So my question was, can a pre-1985 K-frame mount a 7.5, or does it require swapping a K-frame from a Celi-soup or an 85 GT-S?

Any info would be mega useful!

[Teranfirbt]

The F code diff will fit into a T code carrier with a couple of mods. The side mounting holes are slightly further apart and there is a 4th hole on top. You can probably get away without the last top bolt, so just slot the side holes a little and mount away. The supra k frame does get you rear disks.