318 build up

12 second 318 huh?

I'd start with a zero deck piston. KB hyperu's or a forged Wesco, etc....
But the piston goal is zero deck.
Stock rods are more likely ebnt, Eagles are cheaper and stronger to use, food for thought only.

bowl ported and gasket matched 360 heads with a well done valve job and stainless steel valve also back cut @ 1.88 - 1.60

M-1 single plane intake or Edel. RPM for more street bound rides, 750 cfm carb, super comp headers or TTI's, windage tray, accleration baffle in oil pan, chrome box or MSD, build up that tranny nicely, stall with held for cam and weight considerations, 4.56 gears and 28 inch tires as fat as you cn gett'em under the car, (Do a thread search on this) Connect the frame, Pinion snubber with S/S springs or Cal-Tracs, 6 cyl. T-bars

Drop the cars weight as much as possible. The 318 lacks torque in a big way and could use a break.

CAM, Oh boy, time for the chime in's, heres my choice........ but first a note.

Mopars 12 sec tip recomends a 276 mechanical cam rated at 234 @ .050 and .490 lift (28/32 lash) Seems smallish to me, but if the weight break is there.....................
I would have said off the cuff MP's 284 mech. cam.

Mopar Muscle did a build up and used a Comp Cams 280 (230@050 ) with the above like build and Magnum heads and dyno'd the engine to 400 HP. That was a bit of dyno time to get it, 380 HP should be do-able.

I'd run a Comp Cams XE274H. This Hyd. cam with it's split duration should help the whole system breath better and perform better as a package.