my first engine rebuild (318) advises

If your block needs to be bored, only then buy new pistons.

Before buying the expensive as heck KB167's consider using these magnum pistons and METRIC rings to suit (file fit is even better).

http://www.summitracing.com/parts/slp-h814cp/overview/

MUCH cheaper than KB167s!

They popup higher in the bore more than stock (not as much as KB167) and are true flat tops with no valve reliefs, the cams you're looking at are tiny and should be fine with no piston-to-valve interference, the pistons will fit on your LA connecting rods but the small end will have to be narrowed.

If you go for these or the KB's you will need to get your rotating assembly rebalanced.

If your cylinder heads need a valve job, consider buying 2.02"/1.6" valves.
This will help bring your compression up slightly by about 3.5CC and increase cylinder head flow dramatically

http://www.summitracing.com/parts/mil-45640-8/overview/
http://www.summitracing.com/parts/mil-45645-8/overview/

For your stated needs I would not recommend spending any money on port work, you won't notice it when driving.

You will probably need new cam bearings, main bearings, big end bearings, fuel pump, water pump, oil pump etc so be sure to factor these into your budget.