Internals can be switched over to a different case.
I’d probably go 572 over 598 just because I’m not a fan of boring a block out to max on its first build.
Power... 1,000 hp is pretty easy with a big cubic inch motor.
If you use an Eliminator block the maximum bore is 4.700 so a 598 would leave plenty of bore. The Kaase SR-71 heads will do over 1000 hp and you can use a standard intake. The headers should be a little more readily available too.