What is the "common" HP limit with an 05 LLY stock internals before pistons/rods/pushrods start to fail? I know their is alot of factors that play into this but what is the general HP area where stock internals start to fail?

-Nolan

What is the "common" HP limit with an 05 LLY stock internals before pistons/rods/pushrods start to fail? I know their is alot of factors that play into this but what is the general HP area where stock internals start to fail?

-Nolan

I would say anything north of 600hp, but there have been some that have failed with less.

Without getting into specifics, if you get aggressive with boost you'll blow the headgaskets easy. I've heard of guys running 50 PSI of boost with no head studs, but that much boost with no studs would scare the hell out of me. As far as HP, a lot depends on how you drive the truck, but as you get above 550-600 HP your risk of tearing something up rises. Don't forget, the tranny is the weak link on a high HP truck. A stock Allison will only take about 75-100 HP over stock power levels

What type of life are you looking for? Typically if your looking for 25,000 or more out of your motor I would stay below 500 RwHp. Typically a well done 450 RwHp tune is more than most will ever need. The truth is the longer you run at higher than stock power the quicker it fails. So if you have the tune running at 500 and never go full throttle it will last much longer than the same tune if you go full throttle daily.

Currently have built trans and in the process of changing head gaskets (with head studs) right now. While im here I'd like to add a larger turbo and maybe %50 over injectors but I want to stay safe because the vehicle needs to last. Im torn on which turbo to get because I don't want to get a turbo thats capable of 750 hp if im never going to be running that high. My plan is to leave stock crank/pistons/rods and make the most reliable power. What starts to fail when making excessive hp?

I made 541/ 1029 tq this weekend , stock cp3 - stock inj. & a Danville 2.6 stg2 turbo . I'm very happy with how it runs on the street (don't tow much ) I want to twin it someday (billet s475 ) .....

If you go past 600 you should consider rods

Talk to Danville performance 317-745-8587. I made 702 at the the rear wheels with the stock bottom end. Mark knows his stuff over at Danville. I know my engine is not in a full size truck but it has been running great for me.

Currently have built trans and in the process of changing head gaskets (with head studs) right now. While im here I'd like to add a larger turbo and maybe %50 over injectors but I want to stay safe because the vehicle needs to last. Im torn on which turbo to get because I don't want to get a turbo thats capable of 750 hp if im never going to be running that high. My plan is to leave stock crank/pistons/rods and make the most reliable power. What starts to fail when making excessive hp?


If your lucky head gaskets will start to leak but most of the time it bends a rod. If it's a rod in the center 4 cylinders it will start running rough at low engine RPM. If it's the front 2 or rear 2 cylinders by the time it happens the rods comes out the side of the block. This is due to how the crankshaft is made. The other failure is a cracked pistons and if that happens it will blow oil up out of the fill cap and dipstick tube.