You might think me crazy but I bought the composite body Street Demon a year ago to put on my magnum crate 360/320 with a 2 plane M1. Yep, call me crazy. Replaced a Holley 750dp that was running ok after a rebuild but it's a 727 car and wanted to put vacuum secondary's back on it, so I took the chance. I took the chance after reading all I could about it and looking for all the intell that was out there. Heck, I didn't want to spend nearly $400 smacks on a carb that didn't give me what I wanted, especially a first year unproven model. What really sold me was that even for a flow of 625cfm, the carb had enough flow to dyno out a big block at 425hp which told me it would have plenty of flow potential for my unmassaged cast iron magnum heads with long tube headers.
I'm not a big fan of Edelbrock Carbs, mostly because the few I've been associated with in the past just didn't have the greatest response when you mashed the pedal and lord knows we love to mash the pedal. Nonetheless I was also concerned that the Demon was just another Eddy and I'd be stuck with a paperweight when I was done. Holy cow did I make a great choice. I absolutely love it. Easy tunability, idle control, smooth quick throttle response and "ohhh my God" pedal mashing kickdown launch.
I'm going to try an Eddy RPM air gap next just for fun. Happen to have one on the shelf here.
http://www.demoncarbs.com/Categories.asp?#Carburetors