Mill decisions

I'm saying very few Fords survive it using nitrous for very long, which is why there are other cheaper better block choices. You want 700hp, but you're doing it in a fairly violent and unforgiving way. Turbos would be better, and not as hard on the block. You can make the power. Anybody can make the power using the right parts. But for it to live, is entirely another matter. And if you're spending on the lower end to be reasonably safe at over 600hp, you're within hundreds of the cost of a block that will survive much longer, and make more power. 600 is the reasonable limit for NA or NOS use. I also use that for supercharger builds, because the drag on the crank nose can strain a block and crank. The numbers you want are not unrealistic. Expecting it to come from a 40+ year old factory design with some buttressing, and do it for very long, is simply not a solid expectation. I think instead of $5000 heads and valve train, I would buy the best block, crank, and rods, put heads that can move enough air to make 500hp on thier own, and pump laughing gas thru them to get the numbers you need. Better foundation= more power over a longer life span. The same Ford fellow I recall used Big SHot systems and Foggers to run high nines in his Fox Mustang and a 302. He split three seperate 5.0 blocks down the middle on NOS. He now runs a single turbo, much better block and rotating assembly, and the same car (with updates) runs mid 8s on street radials and makes tons of money on the street racing scene. If you saw it, it looks and sounds like a 12 second car.