The Department of Corrections: Don’t Trust the Salesman

The LS Truck block is sometimes the bain of the swap world. It’s not a bad engine, it’s just one that’s easy to go wrong if you don’t pay attention. Even experts will say they have a 5.3-liter when in actuality they have a 4.8-liter. In our case we thought we had an L33 5.3-liter for Project Ron Burgundy but it turns out we didn’t. Sometimes, it’s best to not trust the salesman. It’s not all bad news as we do have our hands on a LH6 and we’ll show you the differences and how to spot it.

So, yeah, turns out our “L33” is actually an LH6 and I have 1FastBrick here on LS1Tech to thank for helping me realize that. Though, I was a bit stubborn at first. I mean, seriously, how would someone advertise this an L33 instead of an LH6? Welp, turns out the guy did. Not all is lost and even 1FastBrick said it’s still pretty much an L33 at the heart but with a newer Generation 4 design. That being said, this is also not a normal Generation 4 LS.

First thing you want to keep an eye out for when you’re looking at a potential block is this: the valley cover. You can see it doesn’t look anything like a Generation 3 and, most importantly, gives away that this is an engine with AFM – Active Fuel Management that gets called “displacement on demand” by many enthusiasts. The big give-a-way is the connector at the back. On the Gen3, this is where the cam sensor is normally located but on a Gen4 this is for the solenoids that activate and deactivate the AFM lifters. You see this connector or this type of plate, you have a Gen4 with AFM.

With that being said, you’d expect more Gen4 stuff especially in the timing side. Fortunately for the LH6, this is where things start to look more like an L33. The cam gears you see here are 3-bolt cam gears but the one on the left is a 1X gear you’re used to seeing on early LS engines. The one on the right is a 4X, which you see on later LS engines and those with AFM.

However, the LH6 comes with a 1X cam gear. That’s not all…

The later generation LS-engines come with a 58X reluctor wheel and matching crank sensor like the one on the right. The previous generation engines came with a 24X reluctor and matching sensor.

The LH6 comes with a 24X reluctor and sensor. What’s going on here? This is a Generation 4 build but with Generation 3 parts? Well, the answer is fairly simple. The LH6 is designed as a carryover.

In 2005, General Motors released the LH6 to replace the LM4. However, for the GMT800 pickups (pictured above), it was only used in the 2007 Silverado Classic. The GMC Sierra, though, used it until 2009.

Yeah, I don’t have an L33. Yeah, I was sold the wrong engine. However, the end game hasn’t changed just because this is an LH6. Everything from the L33 will still work so all of the parts I have will swap over, including the wiring harness. A few small and inconsequential things will have to change but Project Ron Burgundy is still getting a lightweight, aluminum V8 that makes 320-horsepower out of the gate. Just wait until you see what it makes with that Texas Speed and Performance camshaft.

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