Took me a while to find this thread - been pretty busy.

The components of the stroker kit may be able to handle that power level - assuming forged pistons and the H beam rod uprade - but the 390 block will be well beyond its design limits. Adding cross bolts will help - but its still gonna be pretty marginal if you really get after it. You'd be bettor off saving up for an aftermarket 427 block - they are much sturdier.

The Blue Thunder heads have made over 700HP naturally aspirated - so your power level is easy to reach with those. It would take more boost to hit the number with the Edelbrocks - but I've been well over 600 N/A and around 650 with a Novi and 8 lbs on a real mild 428 - so it's "doable"..