Small Block 318 edelbrock carb

slant
both of those avs carb will give the same mileage as the primaries are the same size
the air valve secondary (avs) will only open as much as you need
if a choice the avs2 will give better mileage and throttle response
that TQ clone would be even better
or you can come over and go through my TQ stash and we can find one for a 318
you would need a spread bore manifold, not hard to find
you need the right kick down no matter what you do

here is a TQ list we could print out before sorting through the stash
Fuel Injection or Carburetion ?