Well...keep in mind I'm no expert.

Pistons, piston rod and I understand the way the wrist pin is used are all different. This make for a system that can better handle the power.

So much mis-information in this thread its not funny...

Then take a moment and inform us, quote sources and get it on the right track instead of merely mentioning it. We don't claim to know everything or have shunned learning.

The L36 M90 kit has proven itself. It isn't cheaper to get a new car, and it'* almost rediculous to do something like that. Top end swaps are fairly cheap, and with a good tune they are fast. A lot of people are doing them. There'* always risks to modding, etc etc. However, someone with the right knowledge can do great things with this. We all know this...

Yes Sol...we have seen many swaps. However the question was about the lower end and what differences etc. And the effects of power on the L36 lower end.

I'm looking for a more technical information than "we've seen it work well in many cases". This we know. Your response is about as informative to the members of the club as "there'* so much misinformation here". Step up, contribute what you know by posting the technical information. Let'* stay away from biasing our views or our beliefs and honestly document data to prove or disprove theory and misinformation.

Can this motor be run and abused for 100,000 miles w/o suffering a problem?
How much weaker if at all is the L36 lower end to the L67?
Why would GM Engineers design two different lower ends and not take advantage of the possibility of more power, there is a reason and it'* in that bottom end.
What is the breaking point of an L67 piston and rod?
What is the breaking point of an L36 piston and rod?

Until we get data and facts.. post them and prove the information... all of us are merely speculating.

To start,
A stock L36 bottom end has put a GPGT into the 10s. So as far as the maximum power it can take, that should give you an idea. That isn't a good reliability indicator but it'* a start.
IIRC the ring lands on the L67 are thinner than the L36s to combat emissions. A common failure for the L67 is chipping pistons, so the pistons hold up better in that reguard.
GP guys have also been putting those 4t65-e diffs through hell too. dbtk2 has been for a while and I believe Timperwarp on cgp put alot of miles and track time with a 300+whp csc.

The top ring groove on the L67 piston is lower to prevent chipping under high boost. This is true for Series 1 and Series 2 when compared to the L27 and L36 pistons.

We won't get data and facts until more people try these products out. Need a good sample population, and more guinea pigs.

Let'* keep in mind..this isn't an aftermarket offering. This is the stock bottom end assembly from the NA motor. There'* no "product" offering.

GM Engineers tested these things before putting them into the drivetrain.

I was referring to the M90 kit.

If we are to test the durability of the motors, more people should be willing to throw more power at them.