stroker kits are a good choice but then you'd have to do some top end and cam work as well so your budget would probably double.
I got my 347 stroker kit and my 408W stroker kit from fordstrokers.com and everything was PERFECT, great customer service and fast shipping too. I know you can get a budget (cast/hyper pistons, cast crank, I-beam rods etc...) for around $700 shipped. then $150~ for a cam kit from Summit but then you'd need top end work. intake, heads EFI/carb and then of course headers and exhaust so kiss the budget goodbye.
I'd say for power on the "cheap" boost. you can get 400HP plus out of a stock 351W longblock on boost. You could do it for under $1K as well. I sent you a couple options via PM, an N/A 400HP~ build and a boosted 400hp~ build, both around your $1K budget.