I personally would have moved to a spool mount instead of using the biscuit style.
The spool mount small block to big block modifications has been done forever. As well the K frame was an offering from Mopar way back off the shelf, over the counter.
I did a small block K and put a big block in using biscuit mounts in 1990. I would however use spool mounts , mods were no biggie .. fit like a glove with factory BB manifolds, power steering and power brakes. I never moved the steering box or had to consider it. If I was to consider it geometry would have been a major consideration imo.