'69 Barracuda T56 swap, floor, cross member

You’d need to lower the torsion bar anchors in the crossmember to do that yeah? Or raise the LCA pivot tube? You can’t put much angle on the bars before they bind. I’m not familiar with all the tricks they used on the hemi cars
A lot of ppl put spacers between k frame and frame no issues with torsion bars and steering shaft. But it does change the camber. Usually 1/2" or less spacers don't cause too much of a camber issue. But k frame spacers definitely change drive line angle although ppl who added spacers never complained about vibrations maybe they stayed within angle tolerances.