Would a set of 70 up B Body LCAs work on a 67 Coronet, the sway bar mount location would be different so a later sway bar would be needed....I think it should just want a gut check..
If you run a 71-2 LCA (73-up are different), you need to run a 71-2 bar. You can also run a E-body LCA, but you'll have to run a E-body bar.
Here's front sway bars in a nutshell for B-bodies..
66: very rare, so rare the parts manual I have doesn't even list it, and only seen it in the FSM and on one car.
67-70 same LCA/bar setup.
71-72 same LCA, different bar setup. (E-body LCA will work as well, but requires E-body LCA).
I know some people don't like the aftermarket LCA's that mount to lower shock bolt, I was leery of it as well. I've run one for many years and never had a problem with it
Aftermarket LCA like from QA1 will work 66-72, but require a 71-72 b-body bar.
I own 2 1966 Coronets, both original big block cars. Both were built with front sway bars but they are different.