You will really enjoy the blower. 9:1 is doable but, not the best way to go. anything between 7.5 and 8.5:1 is where you want to be. I would not be so dead set on a solid roller, you really don't need it with a blower. A solid flat tappet will make all the power you can imagine. You don't need to RPM the engine with a blower. The beauty of roots blowers is the low end torque they make. A head, cam, and piston swap and you will be in business. You don't want to lower the compression using a thick head gasket. You didn't mention how large your engine is but, with a blower 215cc heads will be just fine. You kind of have to change your thinking aboutport size and velocity when talking forced induction. My heads started life as 215cc (Darts as well) there has been some port work done so the port volume is now a little more than 215cc, my engine is a 388. I have an 8-71 on it and run it underdriven still makes 12lbs of boost and the torque is just stupid. As far as the cam goes I recommend calling Mark Engle at Engle Racing Cams, he took real good care of me and ground a cam that does EXACTLY what I asked for (it's a solid flat tappet). Tell him what you want and have your car details ready, hthey are good people to deal with and listen to you, they won't force anything on you. They will work with you to get you what you want.
Mark,
Nice looking project. When you get a chance hit the "pictures" link in my signature. We have similar taste it appears. My project is not back on the road yet, hopefully in a couple months.