Hey ObscureMachine,
Similar to others found my roller 351w in a wrecked 97 F250. $200 at the local U-Pull.
I was always told to figure about $1k for a good machine shop effort. I came in slightly under that at about $900. Magfluxed, pressure plate bored .030 over, line honed cylinders, line hone/square mains, line hone cam races. Fully decked and squared head surface. Machined for stroker rod clearance. Acid/hot tank, shot peened, new freeze plugs, cam bearings/plug, oil galley plugs. Late model 351w blocks have a tendency to crack btw at the middle cam bearing race, have this checked before doing any other work on it!
I picked up a 408 Stroker SCAT rotating assembly from Summit after shopping around a bit. Agree with most here that this part takes a bit of calculation knowing your stroke, deck height, gasket height, piston dish, head cc's all comes into play figuring out your compression. Few missed calculations her can mean the difference between a whole lot of fun and whole lot of detonation. Paid about $1100, kit 1-94306.
Would agree with the rest on the Alum heads. I found some GT40 replicas in aluminum on Ebay, brand new. 64cc chamber, 190cc runners, .530 lift for about $650. Still need to add rocker studs, pushrods, rocker arms, etc...
As for the cam, this is where we all get to do what we want! I like a bit of lopey sound and will likely go with a Ford Racing Cam (E303) or a Comp Cams Magnum (35-440-8). I found the software you can download from Comp Cams called Cam Quest to be really useful for playing what-if with the cam calculations. Also as mentioned before I sent them a note asking what they recommended and they got back to me in a day with kit options etc...
All in I figure I will easily be $3500 in the fully balanced and assembled long block. I'm going carb and quite a bit of whats on the old tired 69 351w will move over, however stuff like new oil pump, new dizzy/ignition, gaskets/seals, harmonic balancer, bolt kits, timing set all add up quickly. Maybe another $500+
Hope this helps, good luck!