Stock port 915 heads.

Mani port = 1.275" High

head port...tough to get verniers in there accurately, but around 1.100" or so. Non-ported.

exhaust leak...

John, the heads were in excellent condition all around. They were prepped by a professional head shop, and to the best of my ability, do not appear to be the source of this problem.

Still waiting on manifolds, so nothing else to report.

Just wanted to close this thread out.

Installed a different manifold, and I opted to go with Fel-Pro Gasket, Dry. Noise is gone.

I still have a slight, small leak at the headpipe, but as I said, I found a small hole in the weld at the headpipe flange. The "noise" is 90-95% gone, thus I can start worrying about something else now. Thanks to everyone who chimed in.

One additional note... Yeah, that was exhaust noises, and the manifolds are about 50/50 as to whether they seal or not. I use the fel pro stock ones, and most importantly regardless of manifold or header, or gasket type, you need to torque them fromt eh center two out. Never the ends in, or from one end to the other. If the manifold is a little warped, tightening from the center may help pull it flat.

Moper:

Right, like anything else, center to out for tightening sequence. I can't really get a torque wrench in there, and the nuts are listed at 30 ft-lbs...but I'll keep on eye on them, and re-tighten after the thing runs a bit more.