Epsilon Plus

2020 through 2023 have no changes down there. They will fit.

4x4 models: Plastic Steering Shield: 84154539 Z71/X31/AT4: Oil/Engine: 84154831 (4 bolts needed) Transfer Case: 84154540 (3 bolts needed) ZR2/AT4X: Front (replaces plastic steering shield) steering/oil/engine: 85637479 (4 bolts needed) Transfer case (requires rear holes drilled for 20-23 models and *possibly 24+, unconfirmed*): 85569359 (4 bolts needed, 2 may need to be custom length with nuts/washers for 20-23 models drilling the crossmember, 24+ might be pre-threaded need confirmation) Bolts for all (M10X1.5"X25mm): 11518341

Deep in the vaults of GM engineering I'd imagine.

A bit softer. Like going from a covered wagon to a Model T. Spring rate is just too high on the torsion bars and rear leafs for the shocks to even be involved in everyday driving unless you are loaded down. The only way I think you can really soften this truck up is with Cognito's comfort ride torsion and leaf set up. -25% rate, but also -25% payload/capability. I'm not willing to un-HD my HD. I'm on 37s with 45psi front, 40 rear and the wife still has to be mindful of slight cracks in the road when taking a drink of her water cup or she'll be wearing it. I would do it again. Price was right. No aftermarket jank. Factory driving characteristics/capability. Perfect for me stance. Fit 37s. Cons are that it is a ton of work for a baby lift. Being that you have a 24 though you might be able to run the DSSVs. Still a mystery on whether all 24s got the hard brake line change to allow for the massive shock bodies.

I highly doubt there is any change in axles. The differential carrier bracket difference (diff drop) is to correct the angle of the CV. newdude would know for sure but he's already investigated all the part number differences. The only thing that's still kinda up in the air about the full swap is the DSSVs on 24s. There was a hard brake line change that a forum member was dealing with but it never really got resolved. All that is confirmed is that the DSSVs won't fit 20-23 trucks without changing a hard brake line to accommodate the massive size of the shock body. Still unknown if ALL 2024s got the hard line change and can convert to DSSV or not.

I think GM dropped the ratio down on the gas trucks because they figured the extra torque of the 6.6 could make up for the drop while trying as they might to not get the worst MPG of any modem vehicle on the road . I average 11.5 city on 37s. Pretty sure if I had 4.10s and especially these new canned tunes coming out with 50+more torque on 91 octane I'd be rivaling the fuel mileage of an LS-6 Chevelle.

If you plan to drag it on some rocks, flip it around. If it's going to end up where most of these rigs will, on a fire road or the Home Depot parking lot, I wouldn't sweat it much. HK_Crew makes a good point though.

Scores of fleet vehicles go the whole 7,500+ interval and get the cheapest service parts available and go 200+k miles. Spend some time looking at BIOTG forums and people that submit their oil reports to Blackstone labs and you'll see the modern Dexos 1 Gen 3 oils are good past 15k. I know every car guy loves to change it every 42 miles and keep it nice for the 2nd and 3rd owner in a few years, but I'm just playing devil's advocate that the statistics say it's overkill. Freeport-Mcmoran or the City of Insert Name Here is going to have a blue collar in an HD idleing it 6-12 hours a day for 100,000+ miles while it gets computer triggered PM services with the cheapest stuff they can get bulk. Then, after it goes to auction, it's going to end up a landscrapers truck for it's next 200,000 miles getting the same or worse treatment. Meanwhile, you'll change your oil every 5 miles and give it the best parts and it will spin a main bearing at 42,000 miles. That's just how this stuff goes unfortunately.

Bump

I have also thought about cutting the hood inlet pieces off the diesel box and bonding them to the gas box. Even if the S&B diesel box fit, it has a hard duct to the throttle body that is in a different position than the L8T. The stock setup uses a flexible bellows that attaches right at the lid and makes the swap easy. However, if the box did fit making a custom TB connection and eliminating the Hemholtz resonator would probably be easier than dealing with the oil line. My buddy has a 3D printer but I dunno the first thing about them or how technical it would be to recreate the lid with a lower frontal area.

Alignment can get all jacked up when playing with trim heights. Once you get a truck where you want it, it's a good idea to put it on a rack. "Safe" bet is relative though. Without proper UCA angle your ball joints are going to get eaten up. You'll also have even less travel and be maxing stock shock rod travel. Torsion cranked trucks are known to ride like crap. Must be bad because I think stock HDs ride like crap . GM thought 1.5" was enough to engineer a bunch of new part numbers. Doesn't sound like much but keep that in mind going forward.

Not sure how torsion bar settings would push the rear wheels out of the wells. ZR2 is a 1.5" lift. UCA, LCA, Knuckle, and Diff drop bracket for each side. 1.5" spacer under the rear leafs in the back. Factory spec ball joint and CV angle. It's a lot of work for 1.5", about equal to what you'd do putting a 3-4" kit on. However, no aftermarket jank or cutting and the aforementioned factory designed suspension geometry.

It's not wise to place yourself into the DEF/DPF modern diesel emissions nightmare just because. Also nobody has mentioned that the HDs ride like covered wagons. My wife can barely get a sip out of a cup without wearing it on a smooth road and I'm on 37s with 18s (lots of sidewall) at only 45psi. 3,500+lb payloads have savagely stiff springs that sailboat fuel can't compress. Shocks are practically worthless empty (I have driven with only 3 with no change). Sound exaggerated? Good. Because people justifying their purchase from the other point of view will tell you how it rides great and blah blah. It scientifically can't. Again, torsion bars and 3,500+ payload leafs don't compress willy nilly. Cheers.

I thought about doing a 90° AN fitting and a braided line. Turns out, I think that's an engine oil cooler line.

The S&B and Banks both look bigger than stock so not surprised. Thanks though. I'll probably try modding the top of the lid and playing with some plastic moulding/welding since I'm stubborn and like to tinker. Unfortunately, even if I get it to work it won't be a plug and play drop in mod for everyone else like I was hoping it was. My buddy has a 3D printer......hmmmm lol

Top down shot of the straw that broke the camels back on this mod. From pics online, diesel doesn't have a cooling pipe in that spot. Unless the S&B or Banks is somehow smaller or misses that area (doesn't look like it from pictures), this mod is officially dead. Can't move the box back because of the battery and needing to line up with the hood. Unfortunately, even with all that massive room under the hood, this particular space is tighter than a frog's ass. Sometimes you win, sometimes you lose. RIP L8T hood mod.

Conflating brightness with increased actual down-road performance is the most common theme when doing just bulbs. Just because they fit and they are bright does not mean they are working properly. Tons of articles online about this from actual automotive lighting engineers. Does it do what you want for cheap? Seems so. But it's like putting a spacer "leveling kit" on a half ton. It may do what you want but that doesn't mean it's the right, best performing, long term success way to do it. Did I put a spacer level on my half ton when I had one? Yes. Did I argue the merits of it over the proper diff drop lifts and coil-overs for the price? No. But y'all do y'all.

Keep justifying your bandaid at the cost of everyone else on the road. Who cares about them? At least you got that sweet glarey off-color look you were going for right?

Air box lid is going to need some wizardry. The plastic tray thingy on the battery needs to be shaved or the battery moved back towards the firewall 1/4" (might be able to loosen mounts and shift it). Diesel must have either a narrower battery or different top tray. Larger issue is the front of the lid interference with the front transmission cooling line. Diesel likely has a different entry point or something. A Dremel to the outter casting webs of the lid may take care of it or else something more drastic is needed. Unfortunately, I'm very limited on time to play with it right now and it's also the middle of Arizona summer so I'm going to shelve this for awhile. Maybe an S&B box might fit better there but at those prices I'm not going to be the guinea pig just yet. Everything else dropped right in. Only the lid and it's aggressive casting material webbing is the road block now.

Leave it to "gm" marketing to obfuscate. https://www.chevrolet.com/performance-parts/crate-engines/lt/lt1-wet-sump

Looks pretty good. If I didn't love the Alaskan editions so much I probably would have gone this route. Looks like they are made to work with 37s using the ZR2 bits.

That's not making it through a filter and debris that big if stiff enough would already have your main bearings singing bad tunes. I vote it's external crap that fell in the pan. That pretty much robot built engine isn't put together sloppy enough to drop that much gasket or sealer.

What are you pulling?

Using factory converters? Put a race shop built converter in like Circle D. Doesn't have to be high stall or race spec but the internals will be hand made stronger and have a much stronger and longer life lock up clutch.

The cam is an LT2 cam. PN 12736191 Interestingly enough, the LT1 cam is much bigger. Like LS donkey bigger. LT2 cam: .549/.549 lift. Duration is 218/231 LT1 cam: .561/.531 lift. Duration is 242/244 . That's monstrous for a stock cam duratuon. That's the duration of the Tick Polluter I had in an LS2. I'm thinking an even more wild but still mild (because of conservative auto mfg LSA) L8P would be to use the LT1 cam instead of the LT2. That big duration with this displacement and long intake runners should have the motor doing ~550 over the L8Ps 523.