If max power is the point, a 340 would be the answer, whether stock stroke or stroked. Using the same crank and rods in either block is just a few cubes difference.
The larger bore 340 will have less valve shrouding which will help breathing. Knowing that, cam selection can compensate some along with judiscious porting.
Again I would say if you have a 340 or 360 then use it. If you have a 318, build it with the research and correct parts combination to build a strong runner and be happy.
The biggest cause of the 318's bad rep is the cam the factory installed. The Chubby 305 has a similar rep for the exact same reason.A friend had a 1980 Pontiac 2dr with the sloped back window that had the 305 4V. Pretty regular oil changes and the car lasted longer than him. 440,000km or about 243,000 miles. The plastic cam gear finally packed it in so he had an RV style cam installed with a double roller timing set. The heads were never off and it ran well. His brother has it now. So the basic engine is not the problem. Pull the stock cam and use it for lawn darts.