Finally get to pretend I am one of the cool kids - Holley kit swap

I guess maybe it was like this from the factory, but I'd do a couple more measurements before slotting and moving the K frame over as that is going to alter your suspension geometry as well. 1/8" probably isn't a big deal and you could likely adjust most of the domino effects out, but shifting the bottom side of the suspension over while the top stays in the same place would affect your camber side to side. Steering should theoretically stay centered I believe because the whole system moves together, though your column would have a very slight offset now that should be taken up by the couplers, so probably no issue there. I doubt 1/8" either direction would affect torsion bars either, but depending on your headers that could just move interference to a new location. I know the TTIs have a spot in them specifically for torsion bar clearance that is pretty tight on my car.

Based on the end of the ears on the k-frame, seems like it is offset to the DS a little. The ears are flush with the outside of the DS frame but inset some distance on the PS. So moving it over to locate the drivetrain correctly would probably make things better for the alignment. But just a guess.

Headers shouldn't be an issue since they are shorties and the only place they are close to anything is the DS header at the inner fender and moving the motor over will make this better. They don't get anywhere near the TB's so shouldn't be an issue there. I should probably look at the PS flange and frame to make sure that isn't an issue but I think it is ok.