Which heads for my 318 ???

No way you get 320 at the wheels without a 100 shot of juice! You may want to reassess your expectations.

T&D rockers.... WHY? Waste of money for what you have. That money is better spent elsewhere, unless you are getting a set for $100 not $1000. Same goes for the Harland Sharps. A set of factory style 273 adjustables will work great and save mucho dinero.