Done lifted 4x4's for years. Including high speed off road. No problem with joint angles. You kits good but not for those of us that don't wanna remake the floor. Tremec has long fixed the shifting issue.Luck to you too.
In the physical world we inhabit, you CAN NOT install a T56 in an A-body without cutting the floor. Unless you lower the entire drive train a couple inches, effectively turning your A-body into a 4x4. Which is a far worse solution than reshaping the tunnel, and has implications that go well beyond abysmal ground clearance.
A well thought out and fabricated tunnel is not “trashing” the floor. If the crossmember maintains or exceeds the strength of the original, the tunnel is just sheet metal. No big deal. A bit of careful fabrication will come out better then what the factory did anyway.
Obviously “purists” need not apply. But a 6 speed transmission is completely wasted on purists anyway.