With the parts that you have a stroked small block would be easier and very likely much cheaper. At 500hp a cast stroker kit is just fine. More head porting and a bigger cam. Those small block strokers run hard.
I’ve had a 360/408 that was really mild that ran 11.00s in a all steel duster, and now have a 511 that’s much more radical in a valiant.
The 408 impressed me for what it was.