How to properly Adjust 1972 Dodge Demon Torsion Bars

That '67 K frame has a different idler arm than your '72 K frame does. They got rid of the single mount idler after '67. So if the '67 K frame doesn't have an idler arm already on it, you'll need to buy one and they are expensive.

Personally I'd keep the '72 slant 6 K frame and just buy conversion mounts. Much easier to deal with.