318 Rebuild suggestions?

AJ has done a lot of tuning and has the engine set up a certain way that can optimize mileage.

But, you will be fine IMO with the 318 and with economy. Smaller engines mean lower pumping losses. You can improve mileage with cam and carb selection; for example, the old Holley 6619 was an emissions and mileage 4 BBL carb from the 70's and can be found, or the new equivalent. Any headers will help mileage too; stick with smaller tube ones.

Mileage/hi-torque cam are out there to be bought readily. Keep the lift under about .450" to keep from having to modify the retainers and guides for higher lift. If this is just for driving around, I would refresh the valve springs with new ones; what will be adequate depends on if you are just low RPM cruising all the time, or will rev it from time to time; please let us know.

A modest compression ratio increase will help mileage too; moving up to around 9:1 true SCR will do the trick for a mild application like this. (Real 318 LA SCR's were low 8s to mid 7's). The hard part is finding cheap pistons for the 318 in that SCR range. The Speed Pro H814CP would get there with some head surfacing, but they are lighter than stock and so would require a rebalance of the crank. (You could probably not worry about the rods for stock, low RPM use.) Sealed Power 526AP's are cast and should be stock weight. They will give you right at 9:1 SCR with .028" thick head gaskets (Mr Gasket 1121G), AND shaving the heads .025-.030" to get the cumbustion chamber volumes down around 63 or 64 cc. (This assumes typical 318 LA heads, like the 675 casting ones.) Note that the the standard Felpro Permatorque head gaskets as thicker and will cost you almost 0.5 point of SCR.

BTW, add valve guides to be checked and replaced if worn. You don't want to do a quality rebuild without getting the valve-to-guide fit back to new spec.

And agreed on the oil pump; a new standard pump and good internal bearing clearances will get you all the pressure you need for this application. A SBM HV pump actually only shows any advantage at low RPM flow and pressures anyway.

Of course new timing chains, cam bearings, and so forth. There is NO need for new rods.

I personally like doing my own work for quality control versus a bought assembly. And you can control the parts selection too.