Edelbrock Heads for 318

Awww, the heat stove and stock air cleaner can be removed once it warms up a bit after winter. Where are you located? It doesn't say under your screen name.

The best castings are the 302's. This being a non-magnum engine?
I assumed. (Eeeeeeekkkk!!!)
But the Magnums are a excellent choice as well if you don't mind the work involved. It's more than just swapping parts out and cutting new pushrods. There could be an issue with hi-lift cams and pistons.
Not the case 99% of the time here.

Besides the Magnum heads, which I'm not to sure on there flow numbers and balance ratio between int. and Ex. I would say, build dependent of course, the 318 head can use a 1.60 exhaust valve first and foremost before a 1.88 intake valve. Back cut both valves and perform some light bowl work. (With the stock intake valve and 1.60 valve)
This would be very good for mild street engines and rear ratios 3.55 and under, er, lower, umm, numerically lower. 3.23, 2.76.

If your running 3.55's and numerically higher, (3.73 to 3.90) a 1.88 valve can be used. It is assumed at this point, your looking for some decent HP from the 318 and your not just piddling around town. Raised comp. ratios, headers and increased cam timing in excess of 224 @ .050 with as much lift as you can cram would be the idea going here.
Around this are or so, one can expect hi 300 HP numbers. This works real well in a Duster/Scamp etc....

Be advised that stock heads have the worst balance ratio between the intake and exhaust ports. On a dead stock head, a split cam of not more than 12*'s is advisable. This extra duration helps empty the cylinder and increases the power via leaving the cylinder emptier for the incoming intake charge of air and fuel. Less exhaust gas left behind is better. With this inmind, even a stock smog head can be made to perform fine. Though they do have a limit, there is probably nothing wrong with it for useage in a mild machine.

Once you start porting the heads, the balance should change with the increased exhaust port work. Less seperation in duration between the int. & ex. can result. Remember, theres also to much of a good thing.

You can do very well with a stock head. The real trick is knowing your parts and what there capable of. Not everything is cold hard facts and flow numbers. But there a great start to your build. Heres the questions for everybody;

What do my heads flow and there % in balance to each other.
(The percentage helps find you a cam. Some need more duration then others and some more lift than others.)
Where does the heads flow stall.
(A point where the valve lifts higher, but the cfm stays the same or worse yet, drops. It doesn't pay to get a cam with a lift of .600 when the head stops doing anything after .480)
Is there enuff port volume/velocity for the intended purpose of the engine build?
(These 2 allmost allways go hand in hand. For the street, hi port velocity should be first. A bigger port, most allways, slows down the air and fuel into the engine. The air and fuel should be kept moving from start to finish as quickly as possible.)

There is a time and place for each head out there and it's starts with the intended purpose of the build. You don't want to use 360 heads on a mild build. You may want them for a street machine/light race build. 2.02's in the head, for the most part, should not be on the street. Theres a fickle area where there OK. But the lose of torque and low speed drivabilty must be met with higher stall converters and numerically higher gears.
Your going to get people screaming there 2.02 J head rocks and rules the world, but I'd be happy to point out a fella or 2 that'll whop'em with a smaller head.
Balance!