318 rebuild
KB167's are a good piston for a mild to moderate build. The compression height is 1.81", which brings the pistons up in the cylinders a good .070" vs the stockers. That alone will get your compression above 9:1, usually close to 9.5:1 depending on the cylinder heads and head gasket.
Been there, CC'd that, usually end up about 8.5, providing he is using the 74 heads.
The cylinder heads are another big area to improve. 302's as DK mentioned are a much better design, but still have small ports. Heads off a Magnum 5.2 or 5.9 work even better, they have a smaller chamber than the 302's and better ports if you're comparing stock to stock. But, you only need to change the heads if you're looking for more than about 320hp. The stock heads will support 1hp per cube without too much trouble. Have the valves enlarged to 1.88/1.60's with a good valve job and you can get to the 300 hp mark or better. More than that though, and the 302's or Magnum heads are the way to go.
The stock 302 heads aren't going to improve HP any over the stock 74 (975 head from memory) Finding a good set of magnum heads is sorta hard, and the magnum heads hurt low end torque, and thats where the "stockish fun" is.... If you DO put a bigger valve in small port heads with no porting, put in a bigger exhaust valve, leave the intake alone.
An Edelbrock Performer intake will do the job just fine, if you stay with the stock 318 heads have them port matched to the Eddy as the ports on even the Performer are slightly larger than the 318 heads. DK is right on that one too, a 600cfm carb of any variety will work just fine.
Just fine for stock heads, yes, the best for stock heads? No. A quick plug reading from hole to hole on any Performer/action minus manifold on small port heads will prove my point.
For a ~300 hp engine headers aren't really necessary. They look cool, and definitely add hp, but unless you spend a lot of money (TTI's, Doug's) the fit usually isn't great, and there's always that leaky header flange, even on the good ones. The stock manifolds are lower maintenance, and for a mild build won't leave a ton of hp on the table.
Headers will make a bigger difference than changing the heads for magnums on a mild build.............. Not necessary, but a real easy way to get HP and economy. Even the stock 2bbl will make good use of a set of headers.
The cam is the next big item. Everybody likes something different, so I'll just throw out the Lunati Voodoo series. A 60402 is a good cam, gives a good sound at idle, performs well, and stays under .500" of lift, which is turning point for valve spring selection. You can definitely go bigger on a street driven car, but after .500" you start to get into having to spend more money on the rest of the valvetrain.
Small port heads, especially small port heads with a bigger ex vlave, perform better over a wider range with a cam of the same duration. (more low/mid TQ) Think ISKY 260, COMP 260, maybe up to 270. Lift around 430-450, maybe 480? Springs to match the cam are needed regardless.
I'd recommend having the block square decked and honed with torque plates too, just to square everything up. If nothing else, you should talk to your machinist about it. It's not mandatory, after all, they left the factory with a lot of variance, but things like that not only help with power, but with the longevity of the engine.
X2, just like he said, no reason to take it to the machine shop, if you're not going to give it the works.
Next on the agenda. Distributor. Chances are your distributor has more than 24* advance in it, look around, find one that you can idle at 12*, and have 34-36 at full. For a mild 318, depending on gears, full advance should be somewhere about 2600-3000, if your gears are in the 3.55 and lower range, full advance about 2300-2500 would be great. Building a strong motor doesn't do you any good with a lame distributor, lots of power can be lost there.
IF you can still get the Mopar performance distributor, I believe it has 24* of advance in it.