Stroker motors

I am currently Road Racing a 446 with a manual gear box. I like the flat torque curve coming out of a cornier with the BB
I want to build an externally oiled BB Stroker and have it survive 3000-6200RPM for 20 minutes at a time.
How big a stroker can i go with a stock Block?

What about cap walk at 650-700hp?
Girdle?
Should i piece a kit together with light wieght pistons, better rods,ect
or are $1995 Source one kits reliable?
Who makes a good kit?
I can't afford a World $4000 dollar AL block
Can I beef up a Mopar Block?
Author: BIGALOW