That is kind of an un-answerable question. 302 in what form.
There have been many a know engine built by race teams that made 900 hp NA. Though all of these used race blocks, canted valve heads (Yates/cleavland style), most if not all were de-stroked and bored to obtain the 302 figure, all were with custom cranks, rods, pistons. McClaren and Cosworth have both done testing over the years with the Ford small block and both have produced engines that made over the 900hp figure- again with some very expensive parts and a lot of engeniering time, and they never got anything they felt was reliable enough at that hp level to be used for there needs. If you want to build a high HP 302 just to say you did or to prove you could, all it would take is $$. Start with a race block with a 8.7 deck hieght, then put in a Cola crank, add some trick titainium rods, Venolia pistons, Yates heads CNC ported by Yates, a ported Victor manifold, 2.25 headers, titainium valves, titainium retainers, vasco-jet springs, a custom roller cam (Int. .725 lift, 318 dur, Ext. .765 lift, 324 dur.)lightweight mechanical roller lifters, a lifter "rev-kit", carbon fiber pushrods, a bench flowed and tuned 1200 cfm carb, bore the block to 4.08", stroke at 2.83". This should turn to about 10,500-12,000 safely and produce about 900-950 HP - Cost: About $24,000, just ask Jack Roush- thats about what they were running in there IMSA cars.