Desperation

A few observations... You're irritated and rightly so. Stuff happens, everybody's human. I would suggest you find a local performance place that can look at everything. Quality "hands on" is 1000% better than any internet jockey's advice..(including this one...lol) I see you're in Canada. There's a guy somewhere up there on the Cuda-Challenger.com site named Neil. He goes by ChrycoPsycho on there and Moparts I think. He's up there too, and seems to have a pretty decent grasp on things. Go find him, and maybe he can help. Now, as for internet jockeys...IMO, the problem may simply be inexperience on your part (may Dad's too..no offense meant) with regard to performance stuff. I'm no fan of Demons. I can tune them, but I find the first step in any Demon tune is taking it apart and fixing what BG F'ed up building it. Drilling holes that they overlooked, removing aluminum particles that werent removed in machining or washing, things like that. Then you can get to the business of tuning them. And that is a bear too. I know personally several dyno operators that consider Demons a huge waste of effort. They simply cannot be brought into the perfect zone of performance in many situations. Some work great, some dont. I find an old school Holley to be worth it's weight in gold. Most of the stuff I have a hand in designing I spec Avengers of one type or another. Because they use many of the same ideas BG has, but they have MUCH better quality control. Everything in a performance setup has to be expected to be tweaked for it to be 100%. There is no "fits all". Not in engine parts, or anything else. Assume that, and you'll only be happily surprised if something is perfect out of the box. As far as inexperience, I know a lot of guys that dont know the sounds a performance engine makes. You may hear the roller rockers, or lifters, or the washers on locking header bolts (until they back out and "lock"), or even the sound of the exh charge entering the header primary tube. Sometimes it's only the choice in valve covers that made the things audible, but for the most part, they are not quiet. In some respects, they are not smooth like a stock setup should be. That's where a set of experienced hands come in. Just to say "That's normal, to silence it you'd have to do 'x' "... Sometimes that's all you need. I suspect if the bog was there in the 340, and is now there in the 360, there is an issue witht he guys setting it up or the car itself. It could be just overlooking something. It could be a belief that there is only one "right way" and if it doesnt run with it, there's a problem. Not trying to bash, just pointing it out. Bad performance is the end result of some problem or problems with various systems all converging in the one car. Ive seen perfect engines hurt by a wiring harness problem. great tune ups ruined by 5 minutes of "I can do better" by someone who shouldnt be playing with tools, and dangerous accidents caused by using the wrong part and that part failing when the driver needed it most. Stuff happens. The best we can do is try to eliminate the issues one at a time until we're all satisfied lol.