The stock LBZ charger will spool the best out of the factory lineup. As for max power potential between them, that I do not know. The LBZ compressor/turbine is smaller than the LLY but they (LBZ) have proven to make over 500hp with just a built trans/tune/exhaust time and time again while still maintaining great driving manners.
I just did twins on my LLY. I don’t want to tear back into it as things fit really tight in terms of clearance. I’d make sure you have all the maintenance nuance things done and have a good base to start from before going twins. Otherwise, it’s not that bad. Most changes happen when you install the kit so you won’t cross that bridge till you do it. On the LLY, studs and gaskets are a must. If you have the $$, rods are good for LLY, but you are more likely to need pistons on the LBZ.
The factory head bolt is
NOT the reason early trucks have head gasket issues. Factory head bolts are sufficient to the point where I'd be more concerned about factory LB7/LLY rods before the head lifting. The issue with early trucks is the gasket itself. Early gaskets were crimped together. Overtime the layers of the head gasket (they are multi-layered steel, MLS) would shift and cause them to no longer be sealed. The newer construction method is to actually rivet the layers together making them almost impossible to shift between each other. With that said, studs are a worthwhile investment when doing head gaskets as you already have to buy new fasteners since factory head bolts are torque to yield. I just don't want there to be any confusion as to why things fail.
As for LB7/LLY rods, I wouldn't condemn them on a compound unit for something like a S475 over the stock VGT. A good tuner will know what to do in order to give it the best shot at a long life. Larger injectors do help keep them alive by reducing timing/injection duration thus reducing cylinder pressure and lessening the loads on the rods at the same power level.
Good to know thank you. I did compounds on my Cummins I had and I absolutely loved them! I wouldnt being doing studs and gaskets until it pops though - not looking for anything crazy hp wise - just 500whp that runs cool would be good with me...I've got a race car with 1,500hp that can put a smile on my face otherwise. lol (Not to mention that's why there's no extra funds for HG's or studs or pistons! :roflmao
How well does yours tow? I was basically thinking about a setup just like yours so I'm curious how well it tows and what the hp #'s are and EGT's?
If you're looking for the
ULTIMATE in terms of a towing experience, nothing beats a S475 over stock kit. At the ~500hp mark I wouldn't be too worried about the bottom end, especially with quality tuning. The normal failure point on the LBZ is the pistons. It's a crap shoot as to if/when that happens. Some guys never have issues and beat the trucks like the truck owes them money. Other guys have had pistons crack with a mild or even no tune just driving around.
