It's gotta be nearly impossible to find all those magnum hot rod parts these days right? Took me years to find an M1 and Holley billet TB for my Dakota r/t and that was a while longer ago than I care to admit haha.
I have seen a few in that range of power but they were built 408s with all sorts of nitrous or boost. Good times!
Moved it too
Trick Flow and Edelbrock still make the heads. Both are similar, but Trick Flow seems to have better quality control, so I'd lean towards them. They're actually a smidge cheaper too, last I checked.
Torqstorm seems like pretty good stuff and are a fair bit cheaper than Procharger. Their power claims aren't as high, but I don't see why you'd make any less power running one of their units vs Procharger.
Intake manifolds are tough, not much for options here. The Hughes Air Gap is on backorder again, and I suspect they'll be even more expensive once they are back in stock. M1's seem damned near impossible to find. I think Indy Cylinder Head used to have an offering, not sure if they still do, but I remember them being quite pricey. I do believe that you can get an Edelbrock Super Victor manifold with injector ports machined in, but this is a purpose-made racing manifold that isn't going to perform well in a street application. One could also spend $$$ playing with the factory kegger, but I've yet to see anything definitive to justify even bothering.
There's an outfit that makes (or at least, used to make) custom, billet throttle bodies for Magnum engines, but I can't recall the name. They're expensive, but are as good as it gets. I think Pepper has one on his rig. Otherwise, the factory units can be opened up to 53mm, which should suffice for most builds. I've got a 52 from Hi-PoTek, and it's a very nicely done piece, especially for the price.
Hughes, Hi-PoTek and Ryan offer premade and/or custom cams. Comp Cams used to have a pretty nice selection as well, though I'm not sure how available they are. I imagine one could get a custom cam from them, although I doubt they'd be any cheaper.
Scat and Eagle still offer cranks and rods and Keith Black offers pistons in various metallurgical flavors. Icon offers some pretty sweet forged pistons, but they're $$$.
I wish I could say it was cheap building up a fuel-injected Magnum, but it simply isn't, LOL. Then again, there aren't a whole lot of engines that are, especially in today's economy where a burger basket and a pint at the local tavern costs $20, LOL.