327mali said:
just remember. at about 400 hp that stock bottom end is just about at its max. be careful what you throw at it.
Where did you hear that? My junkyard 6.0 makes every bit of 460hp, bone stock bottom end including bolts.
Truck cranks are known to last to 1000hp, rods and pistons usually start to let go up over 700hp. Nitrous/boost w/ poor tunes kill the factory cast pistons, otherwise they can live a long and happy life. Just ask parish who ran a stock 6.0 bottom end into the high 10s if I remember in a 1/2 ton pickup, or ran a bone stock 5.3 w/ cam into the 9.30s (dyno'd up over 600hp at the wheels) in his turbo fairmont.
GM did a dam good job w/ designing and building a motor that is reliable and can take a beating. The single biggest problem with LS bottom ends are the rod bolts (early motors mainly). Swap these out and have fun. I use to go thru the traps w/ my motor at 6800 and its been spun to 7000 on occasion, I haven't even touched my bottom end.