Those are some fantastic numbers with your setup. What are the planned mods?
However, I also agree with LaserSVT, with those numbers being a cause for concern. Interestingly enough, the pushrod guys were known for cracking blocks at around 450rwhp, and to address that problem, Ford put in an ungodly strong Teksid block (sweet!) on our Cobras. Unfortunately, they didn't seem to budget in better set of pistons and rods, which have a breaking point of right about where you are now.
It all really comes down to how you drive, how safe your tune is, and how often that engine sees some boost. You could very easily survive for quite some time, but the odds are sadly not in your favor.