used billet nitro crank

[LuzRD]

hey all.
i have an opportunity to get a 4.5" stroke used billet nitro Hemi crank. it has some stress cracks from running in a topfuel engine, but i dont think they look too bad. my question is does anyone think its usable in a 1970 Hemi block if i offset grind the rod journals down to 2.22" to remove the cracks, and to destroke it. then use aftermarket 7.1", 2.22" journal rods? (i know i will need custom pistons, and the stroke cant be larger than around 4.15 without needing lots of clearencing work, and custom oiling)
considering this is a $2000-$3000 crank new, that i can get for around $300, and new forged cranks (as well as, original Hemi cranks) cost @ least $800, i figure if its useable, i can get a better piece (billet) and choose my stroke based on how its ground.
ive been assured by the seller that its good for normally aspirated street engines up to 1000 HP, but i want to know if anyone here has had any experience or has any thoughts on the subject.
now i want to make clear im not looking to build an insane engine, i am looking to get around 600-650 HP
with a bulletproof bottomend, so i can build up the engine more later on if i decide to without replacing the entire shortblock.
to sum it all up im can get a $2500 crank (that needs to be ground) for $300, and new 4340 7.1 h-beam rods for $370 (that are rated by the manufacturer up to 800 HP)