1931 ford coup speed mod

Hi,new to thread.
   An older gentleman friend of mine who owns a transmission shop here in
Houston just bought a stock Ford  31 coup . He was asking about where to
start with getting this beautiful auto to go a bit faster, so he can use it on the
road ,with minimal impact on its good looks . My experience and obsession
with old cars starts in the 50’s. So I didn’t know where to direct him .He is
concerned with original looks and maintaining the engine ,and leaving the
cool  spoked rims the same . One thing that came up is the possibility of a
transmission swap .I suggested one off of a a Ranger ,and he thought
perhaps an S-10,perhaps there’s adaptors floating around .Another thought
was a  Ranger rear end .I’m ignorant, but figure that this is probably a really
common pursuit in old car land ,so am seeking opinions from my learned
,masters of the 30’s hot rod ,ancestors
Thanks!!