Screaming short stroke 408 we just finished for a customer. It still has hydraulic lifters and runs on pump gas, took it all the way to 8700 and the valvetrain remained stable. We modified a set of LS3 Fast short runners to work with the LS7 heads. We kept the timing at 25 degrees with the pump gas. It made 688 hp@7,600 but the torque didn't peak until 6,600 so I think this might be easier to race on street tires. I think with higher octane fuel and more timing it would go to 700 hp. This is going into a C5 vette so intake height is an issue but with a better intake it should get above 700 hp.