stock 318 more torque?

Easiest way, More gear. 355s or 391s. From there, small headers and a good 2.25 or 2.5" exhaust.

Next easiest, swap in a 360. Nothing wrong with the 318 but the suffer from 3 problems, Poor heads, way small cam and low compression. Fixing those issue will make a huge difference but they arent cheap.