'68 Dart with a 318 LA - Build Options

YY1 said
Do not assume anything, for example, that it needs overbored or new pistons.

However, with machine shop labor, you may be better off doing a Magnum swap.

That's a 100 HP increase if you don't rebuild the Magnum (and you can find them almost all day long that don't need rebuilt).

And they're a lot easier to find than LA 360s/340s. I personally have not seen an older carbed small or big block with any mileage that didn't have pretty significant bore wear, but it's not impossible to happen.