70-74 E-body
71-72 B-body both are direct swap for what you have now.
70 B-body will be the same in regards to the mods you are making.
Those all will have the hole in the K-member for a pass through sway bar. The 70 B-body K-member has a different angle to the steering box. But since you eliminating the factory box that will not matter to you.
But if you are welding things up it really might not matter at that point. Then 68-69 B-body K-member could be used too. I suggest you get a picture of the underside of the wide sway bar 68-69 style and a picture of the underside of the 70-up narrower style.
For front steer stuff...
Call Dick Ross at Firm Feel and tell him Steve Wall in So Cal with the 68 Cuda told you to ask him about his bolt-on steering arm circle track spindle, splined sway bar, and C-body LCA, K-member setup.
With a front steer rack you have the strut rods, swaybar, and tie rods all in front of the spindle and I think things might get too crowded. Like the strut rods or swaybar needs to be moved behind the spindle. I'd vote sway bar through the area the rear steer center-link used to occupy.