Both prior posts make sense. I know a guy whose running an MS3 in a otherwise stock longblock with a 150-shot and is planning on a 200. If it weren't for his 10-bolt finally taking a dump (and causing the stock 4L60E to break) his bottom end would've been fine. He has it tuned really well though, so I'm sure that helps, but it's my understanding the crank and rods (not so much the rod bolts on early LS1s) are pretty stout and even the pistons will put up with some abuse.
05 Hummer H2 SUV on OEM Air Ride
Forged 11.4:1 408 LQ4 (K1 crank & rods; Mahle pistons)/CPP LS3 CNC heads/BTR Stage IV LS3 cam/home ported L92 intake manifold/ported 90mm TB/custom Volant CAI/mid-length headers/AFE dual 3" CB/Corvette Servo/el cheapo lift/Cognito UCAs/Sphon poly adjustable TA/Sphon adjustable rear LCAs/e'fan conversion/DirtyMax radiator/Moroso catchcan/HPTuners/HID conversion/LED exterior lighting/LED interior accents/Autometer Cobalts/AEM WBPioneer AVH-5600BHS/Pioneer GM-9601/2-Pioneer TS-W310D4s/Obcon Labyrinth dual-12 box/lots of other little stuff