I have a 78 Ranger with a 300 it already gets ~19 mpg. I don't really care about hp or torque my truck is a Sunday driver. I want to know about fuel efficient upgrades.

My motor is bone stock, with stock manifolds, no cat. I'm set for a rebuild in the spring, just because the truck is in peices now for restoation. What would you suggest for fuel efficiency?

 

Build it with a goal of more low rpm torque since more revs to get moving means more
fuel for each revolution, So if you can have the power in the sub 2000 rpm and get it
to speed you will be using less fuel. Buy at least 3 or 4 sets of spark plugs from 3 or 4
parts stores at different times between now and when you rebuild, With the head off
put the plugs into the head and look at the grounding electrode open end, It should be pointing at the center of the combustion center or towards the exhaust valve.
This is indexing plugs and will help ensure a better ignition which will help more to
completely burn the fuel charge, Mark the spark plugs with the cylinder number they
match up with so you will know in the future when you go to swap them out. Also a
high voltage coil and a bit wider gap will burn the fuel charge more completely. For
the best fuel economy a Air fuel ratio gauge will help you to decide if you are running
too rich and need to tune your carb for a more leaner burn. It is a bit of money but if
you plan on keeping the truck then it may pay for itself with the prices of fuel lately!!
Becareful running too lean a oil cooler and properly function water cooling will keep it
cooled when you are running on the lean side.