heads for a 318

Junkyard magnums, good option. I have not heard of drilling the magnum heads for an LA intake? It seems like the magnum holes would be in the way... Maybe I am just not envisioning this correctly.... got pics?

The 302"Swirl port" heads are not going to flow as well as the magnums, but they would be the best option for the parts you already have, IMO. They are decent in stock form and with some mild mods can be pretty good. I good mod is to change the ex. valves to 1.60s if it is in your budget. Or just have them cleaned up, and maybe pocket ported. I also would run the MP thin head gasket with these to give a little extra bump in comp.

RHS heads if you want to build a beast later on. Cost for the heads is going to be more than either of the two other swaps mentioned in most cases. But a very good option to start a base for a higher powered top end(More potential for the money). I hear their combustion chambers are on the large side for a stock 318 though, so even though they wouldn't be as bad as 360LA heads, probably wouldn't be your best option without a lower end overhaul and zero deck or close.

360/340LA heads: too big on the combustion chamber to make any sense. Don't do it unless you rebuild the bottem end and use pop up pistons.... but then you intake is wrong... so again, no sense.