I want more Hp for my 318

If "someday" is next year, don't bother. If someday is a ways off... the 318 needs some compression - more than stock. The rule of thumb is 9.5 maximum static compression for pump gas, although the cam you choose has a bearing on that.

You could "do it right" and rebuild the engine, with higher compression pistons. That means a bore & hone. Stick a good oil pump in it while you're there. Obviously, bearings, polish the crank, etc as long as it's apart. The problem I have, though, is why not spend $300 or so and pick up a 360 to build if you're going to all this effort? The $300 would be peanuts compared to all the machine work and new parts.

The alternative is to do a quickie job, which is NOT all bad. Check compression and make sure it's consistent cylinder to cylinder. Pull the heads and take them in. Get some mild porting, fresh valve job, hardened exhaust seats, and mill .040 or so off the heads. That will bring the compression up a hair. Get a mild cam, a little four barrel, some headers, and call it good.