Looking to buy/build 500-600 fwhp 360

I have a 65 Barracuda with a 8 3/4 rear diff, 3.55 posi, A833 "hemi" 4 speed, and 10" tire.
I am new to the world of Mopars, and the car has a low (10k) mile 360. I was surprised at the estimated low horsepower and now realize the heads and low compression are some of the issues. I put a performance cam in it and some big tube headers. I was going to spray it but with stock cast parts I'm limited. I'd like to maybe make 400 hp without nitrous with the option of a 200 hp nitrous shot. It will be mostly street driven with occasional racing.
I was thinking of stroking this motor and putting forged internals. At this point I am considering selling this mild 360 and going with a crate motor. I really don't care if I have a stroked 360 or not, but it makes sense to just make a 408 if I'm going to buy a forged rotating assembly. Ultimately I'm looking to run 11's. I figure that should be very doable.
So, build it locally or go with a crate motor?
Thanks in advance for your input!