400 stroker rookie

Well that is a lot of engine for a first time build. If you don't have a ton of experience then you're going to need a good engine builder to help you get that monster all sorted out and dialed in. Personally I'd ditch the girdle and I'd return the dual sync and get the Hyperspark distributor. I don't have any experience with the 4500 Sniper but since you have it you might as well make it work. 500 inches is probably big enough to run the max wedge heads but it might be a little soggy on the bottom end. You'll just have to try it and see how you like it. Depends on the drivetrain and the car weight and stuff like that.