Basic 318 Mods

If all you are interested in is a "cruiser", then I would forget about gears and convertor swaps, unless you end up with something like a 2.45 rear gear. Anything from 2.94 to 3.55 is fine for a street cruiser, and if you are going to put a 4 bbl on, find a good Edelbrock performer or Wieand action plus with 600 cfm Avs with electric choke and a good free flowing dual exhaust system. Headers are optional, but again for a cruiser, not really a good investment.
Pretty much the same suggestions as others have made.
Make sure you have the throttle pressure or kick down linkage properly sorted after the intake swap or you could burn up the transmission.
Just my .02.