Look at piston speed for the answer to that question. The piston speed at 6500prm's is roughly 4015 that is the max you want to see for sustainable time. The rev limit of FE3N with stock rods is 7000 and the F2T has a 6500 or 6750 revlimiter. I will stick by the F2T ands limit my self at 6500. The torque should be signifigantly higher with the extended stroke and this will also change the spool charicteristics of your turbo. Also look at Boostedrafi, his car club has a factory crank and factory rods putting down 585hp and like 485 tq. Proof enough for me that the crank is stout.
YouTube - Mecanica Galdo GLC 10.35 @ 139mph