beefing up the stock 318 engine CHEAP mods

Further performance can be had cheaply with milling the heads. Cost for this varies widely. I had a set milled down for $35 and some can't believe it. I see others pay triple per head.

Advancing the ignition will help, but you can go to far.

A simple air cleaner from the local auto store will help.

A MSD ingnition will clean up and ignition issues and will put some mileage in your tank. IMO, this is a worth while thing to do.

IMO, this kit which is preety complete as far as I can tell is a nice package.
Once I had this in hand, I'd port the heads with 1.88 and 1.60 valves (360 valves) and be set up for a good street runner. This should make a easy 350 HP. But cheap is realitive.
http://store.summitracing.com/partdetail.asp?part=CMB-03-0162&autoview=sku