Sorry if I came off like a dick yesterday, I have cam recommendation that will save you some coin and give you comparable performance to the xe268 in a 360. For a 318, the next size down, something like a xe262 will be better suited. Be sure and get new valve springs! Recommend a new timing set too.
Although not talked a lot about, ask for duration @ .200, including this in the story with .006 and .050 numbers; gives one a much clearer picture of whats going on power wise. More @ .200 is more 'power under the curve' usually. Good things.
http://www.summitracing.com/parts/sum-k6901/overview/make/dodge
My advice is to say 1-2 size down from what you'd use in a 360.
As far as intake, try the Streetmaster first.
Another fun tool to help you in your quest is a Dynamic compression calculator, enter engine specs, then cam spec 'Intake valve close @ ABDC' @.050 + 15 degrees, keep DCR close to the 7.5-8.5 range for pump gas.
http://www.wallaceracing.com/dynamic-cr.php
Another important aspect is tuning, hone your chops up on this 318 so when you step up to bigger and better you can get the most out of the combination.
Bigger isn't always better, cam or otherwise. You see it time and time again, little guy with good tune beat big guy with crappy more times than not.
Tuning tips:
Idle screws set 2 turns out to start, keep turning out until it doesn't affect idle. Cupped hand over the carb: rev = lean, bog = rich, read spark plugs to verify good heat range and jetting. Step-up springs are usually most responsive at 1/2 of HG inches IN GEAR. I.E. 16" = 8" spring, give or take a size. If you have adjustable part throttle, adjust it to specs.
Start at 1 light, 1 medium springs in the distributor, lighter springs = faster curve, better response, see how fast you can go.
Disconnect vacuum advance and set inital timing to best vacuum. Performance cams like initial timing, don't be surprised if it's 14-18 degrees.
Set total timing to best response/power, 32-36 degrees by 2500RPM is usually the ballpark. Many folks set timing here and let initial play where it lies.
Lastly, I find that the vacuum advance attached to ported vacuum is best for my combination, hook up to manifold to see what you like best. Total including vacuum advance should be around 50-52 degrees by 2500RPM for good cruising economy. It's usually adjustable by sticking a 3/32 allen wrench in the hole the vacuum line hooks to, CW is open, CCW is closed, 1 turn = 1" of vacuum.
That should get you damn close to falling in love with what you've got. Lastly, listen to your engine, if it likes something, give it more until the RPM falls off, then step back a little.
All this applies to the 360 too.
The stock converter will be fine for now, when you step up to big power, get a good custom made converter to your engine specs. You'll be glad you did, VERY important.
