MY opinion only:
I would run the 3.73s with the 408. Just know it won't be a freeway flyer.
I'm running a 440 with 3.91s and another with 4.10s, and a small block with 4.57s. All CAN be driven on the freeway, I just don't do it much.
Obviously, this will be a fun toy, not a daily driver. It should be a rocket ship with the 3.73s. That should have the same crank speed with a 4" stroke, as my 3 3/4 stroke 440, with 3.91s. For an occasional use toy, it will be fine.
Again, MY opinion only.
