340 magnum from 73 dodge dart rebuild

I''l add a few tidbits in no particular order of importance.
Generally want to over bore as little as possible. More so with a 340, which is (a) somewhat more expensive/valuable than most LA engines (b) can run into issues with a .060 overbore. Its alreadya pretty big bore to begin with. Not much to gain, compession to lose.

'73 heads may have the slightly smaller intake valve. If its needs valves anyway, then put in the larger valves.

As already posted the money saved/budget into the drivetrain. If you want throttle response on the street, hewing close to the earlier factory setup is pretty pleasing. Gearing and some tuning will go far.