Hi Steven,

Mustangs Unlimited and others sell good reproductions of the CJ exh manifolds. The originals pop up from time to time, but are expensive.

As far as the heads go, depends on what you have. I don't know much about the '67 390GT. My C8OE-N heads ran about $2500 to rebuild, but they had cracks and pins, and went to a really top-notch shop since I needed the date codes and all to match. You've got a different situation, and that was five years ago. At that time, a set of the Shelby aluminum heads was about the same price as my rebuild, but they didn't make the Mustang exh flanges, and the Shelby needed the original parts to retain value.

The C8AE-H heads came in a bunch of configurations, and were apparently common on the 428 motors (not the CJ). They are pretty good heads, though. I don't have the specs right at hand, but they weren't much off the C8OE-N CobraJet heads, mostly had the wrong numbers. Cost-effective approach to moderate power.

If you use the big port Ford heads, be careful of too much head work. They end up being great for high RPM, but lose a lot at the bottom. My semi-stock (balanced/blueprinted, all stock specs) 428 runs strong to about 5800 by the tach in the car, and starts down in the 2500 range. Went up a steep freeway onramp the other day, spinning tires through first and second, and had to slow down at the top of the ramp to merge. Not bad for HP or torque.

Lunati makes a "Nostalgia" cam that looks pretty good, and the Comp Cams CCA-K33-240-4 kit from Summit Racing is probably what's going into my hotrod pickup.

Good luck.

Good luck.