After I changed out the spark plugs that had come with it the problem I was having went away. I had noticed the soot on my spark plug boots and it didn't look as though it was coming from the exhaust gaskets. When I examined the heads I noticed that the spark plug holes were tapered but Mike had non-tapered seat plugs in it. When I changed to tapered seat plugs the soot issue went away and the engine ran great.
I called and talked to Mike and he said that those heads should have been capable of using either style of plugs. Maybe I wasn't torquing them down tight enough to make them seal but I was cautious because the heads are aluminum and I didn't want to damage the threads.
I have kept so busy that I've only been driving the Barracuda a few times per week through winter and just around town. The last few times out it developed a backfire when cold that disappears after a minute or so. I may have to re-check the plugs again. - Been too busy with other things to pull it back into the garage. It still runs great once it's warmed up. I ran it through the gears hard a few times yesterday when my son was here. He hadn't ridden in the car since I had the 318 in it. It definitely shoves you back in the seat.