Post '67 K frame in an early A?

The early As are physically smaller through the frame rails back to the torsion bar frame. I'm pretty sure no one is making production header for the B/RB motors. There are motor mounts but no headers. There are small block headers from a few sources. The tunnel in the early As are extremely tight as well. At minimum they must be "massaged" but should be cut for a cleaner look. With the number of things working against installing the B/RB or even a late mode hemi into an early A, the stroked small blocks or slant six Torquestorm remain the best option. Can it be done? Of course! Should it? Probably. Best option? No.