if thats your power goal then you need to start thinking about sleeving the block.
and the ls crank (with 81 bore) wont give you 15 lbft more then the gsr.
and how do you know what rpm your peak rpm will be before you even build the block? its not like the power just keeps going up if you rev it more. fuck if you could do that, id bullet proof my block and rev it to 20k. build your motor, find where peak power is, THEN decide what you rev to. seriously it sounds like you just want to build an engine so you can brag to everyone about it, and tell everyone you rev to 9k. i mean, hypothetically speaking, say you build your engine, and it makes 250whp, but at 8k? you gonna tear it down and start over cause its not at 9k? pick a power goal, not an rpm goal. ive told you more then a few times that from my knowledge and experience that your power will mostlikely top around 8-8.5k, are you still gonna rev it out to 9k just because? or to "hear how cool it sounds"?