318 engine build

I don't think the 318 is an engine that you can make very good power with, without some machine work. The compression and airflow hurdles are very high.

Here's an article that shows what you're up against.

http://www.compcams.com/Community/Articles/Details.asp?ID=1968181674

Don't run the 360 heads. It'll kill your compression even worse. For more info, see this thread:

http://www.forabodiesonly.com/mopar/showthread.php?t=57169

The LD4B isn't a bad intake (and you've already got it), especially for the RPM range you'll be looking at, and it has the 318 sized ports. If you're going to hog the intake ports out to the 360 size, then there are better choices.

Headers and good dual exhaust would help a lot, or rather you're going to have a hard time making power without doing it.

If you've got an automatic, a small stall converter (a converter is the biggest bang for the buck short of nitrous)

Gears. They shouldnt be anything too crazy in a non-overdrive street car, but I'll bet you're rolling something like 2.73 right now. A 3.55 is the highest I'd go if you do much highway driving. If you've got a 7.25 rear, forget everything else and replace it. making more power is just going to break it anyways.

For a cam, I'd do something small from the Voodoo or Comp range.

This is the biggest I'd go:
http://www.lunatipower.com/Product.aspx?id=1543&gid=287

In my opinion, with the limitations you have mentioned, you're best off reducing parasitic losses to gain power, or speed. They'll also benefit whatever you throw in there to replace the 318.

Examples:
Windage tray and/or good oil pan.
underdrive pullies, or eliminating power steering and AC
Sealing it up good so you can use synthetic oil.
Taking weight out of the car. To a point, its the cheapest acceleration you can get.
Electronic ignition with a good amount of advance.

This isn't the sexy approach necessarily, but it does work well, and the money you spend will still be in the car if/when you get a 360 or something.

Steve