I think gear banger has the best point. A 302 based build will get you exactly where you want to be and be easier on the pocket. I have a 331 with 11:1 comp, edelbrock heads, 610 lift cam, 750 dp carb etc and dyno was 385 rwhp. If I put a set of AFR's I will get the 400 hp, and I have a plan for a 100 shot. IMO this kind of power is an awesome street car.
I would stick with the 302 stroke it, turbo super charge whatever, but build it 100% correct and put the additional money into getting the power to the ground. Dropping a 408 sounds great but there is always the hidden costs that you didnt factor in and if your not doing all the work your self it may take a long time.