Please tell me I made a smart commitment....

You did very very good. I had one years back missing the original block' mounts and manifolds. I installed a small block K-member and the put every thing out of 71 charger superbee. including manifokds. 70 or 71 b-body will work not 69 back I used /6 mount biscuits beause they are thicker. And I notched the K-member for the oil pump. and used manual steering and moved the outer column back. I drove it like this until I found the correct parts.