Epsilon Plus

LED bulbs in incandescent housings is a ghetto bandaid. The plastic housings and reflectors are not designed to disperse LED light. People see more scattered white light so it must work and be better right? No. It's ghetto. Morimoto LED replacements (great black friday deal if you wait) or stock LED is the way to go. Waaaawaaaa it's super expensive. Yeah, so is your $50k+ truck that came with garbage incandescents. Quit being cheap on safety.

I am using a Pulsar LT with great results. After a little experimenting with stock size vs current I've got the speedo dialed into GPS speed on the nose with 37s. Added benefit of running 50psi all around with no TPMS warnings as I've dropped the threshold to 45. The reduced throttle delay also gives a great response and helps mitigate the 2-1 downshift clunk as well. Very happy with the unit

Wheel diameter won't be an issue, it will depend on tire width and wheel offset. Stock GM stuff should work fine and may only need minor fender liner trim. This is the small amount I cut to alleviate the light rub on mine. As far as dealer warranty it will depend on the service tech and whether they even notice. All the parts are GM stamped and painted black. No fancy looking aftermarket stuff....etc. On 35s they may just think you cranked the keys. If they were to measure or dig into the PNs they would figure it out or a very trained eye could tell a 24 ZR2 UCA from a 20-23 from the unused top holes for the brakes but most techs are just regular mechanics and not GM shade tree super fans like me. Officially, they have grounds to void steering and suspension warranty because of the numerous changes from stock. I'd rather not have Joey Bagadonuts service tech touching my truck anyway, so it matters not for me but for those concerned with warranty, default to a denial in your mind when modifying to this extent.

Metallic will create an optical illusion of sorts for the eye as far as scratches or imperfections. Your eye is so busy picking up all the glitter in it that a hairline scratch or scrape in the clearcoat doesn't stand out as much nor does general coat of dust, especially on silver. I do not buy cars without metallic in them for that reason. Also, expect all GM paint to be egg shelled. It's not laid on by a hotrod lover and then wet sanded. Everything from a Corvette Z06 to a Spark has that classic GM eggshell finish. It holds up as good as any other modern water based finish does. Get what color you like.

I'd put a Whipple or Harrop on it before I played the emissions problems in the middle of nowhere game of a diesel. Will come out ahead too with the prices of new trucks these days.

Relevant torque specs: Front Lower Control Arm Ball Stud Nut: First Pass 37 lb ft, Final Pass 90 -100 degrees Front Lower Control Arm Nut [2x] First Pass 133 lb ft, Final Pass 45 -75 degrees Front Lower Control Arm Bolt [2x] is torque to yield (single use) part number: 11549229 Front Shock Absorber Nut (top) [2x]: 48 lb ft Front Shock Absorber Bolt: 118 lb ft Front Stabilizer Shaft Bolt [4x]: 37 lb ft Front Stabilizer Shaft Link (end links) Nut [2x]: 74 lb ft Torsion Bar Support Bolt [2x]: 92 lb ft Front Upper Control Arm Nut [2x]: 192 lb ft Front Upper Control Arm Ball Stud Nut: First Pass: 37 lb ft, Final Pass: 90–110 degrees Front Wheel Hub Bolt [4x]: 133 lb ft Front Wheel Hub Extension Nut [8x] 96 lb ft Front Wheel Drive Shaft Nut: First Pass: 244 lb ft, Second Pass: Loosen 45 degrees, Final Pass: 199 lb ft Front Wheel Drive Shaft Nut is torque to yield (single use) part number: 11612295 Front Differential Carrier Bolt (Go from the top down on driver side): 81 lb ft Front Differential Carrier Bracket Bolt [4x] (bolts that go from the bottom up on both sides through the large bracket openings): 118 lb ft Front Differential Carrier Bracket Nut [2x] (bottom up, pass side): 74 lb ft Front Differential Carrier Bolt[2x] (smaller bolts, bottom up driver side): 81 lb ft Rear Spring Unit Bolt Nut[4x]: First Pass: 74 lb ft, Second Pass: Loosen 270degrees, Third Pass: 74 lb ft, Final Pass: 175 - 185degrees Rear Shock Absorber Bolt -Upper: 70 lb ft Rear Shock Absorber Bolt -Lower: 118 lb ft

I wish I could edit the original post as planned, but apparently that option times out. That said, here is some relative follow-up information from the larger discovery thread. This thread can serve as more of an up to date quick reference without digging through the minutia. - This conversion works on both gas and diesel and has been successfully completed using all factory 2024 ZR2 parts on 20-23 trucks. GMC owners should substitute verbiage where necessary. X31 = Z71 and AT4X = ZR2 and AEV Edition = Bison. The swap mules on this site were Silverado but all of this will work with Sierra. - At this time DSSV front shock usage will require modifying the hard and possibly soft brake lines on 20-23 trucks to accommodate the very large shock bodies of the DSSV. 2024+ non-ZR2s may not have this issue but no confirmations at this time. The preferred shock usage with this conversion is Bilstein B8 5100s as the standard versions of them allow for stock to 2" extra lift and are a perfect size fit for this 1.5" factory lift. Alternative to DSSVs if you want something in that quality/performance range try King remote reservoir shocks. At least they are rebuildable compared to DSSV and are of similar price range and arguably superior quality. -85637479 is the confirmed front one piece ZR2 skid plate that replaces the plastic steering guard of all 4x4 trucks and the metal front diff skid of Z71 trucks. No extra bolts are required unless going from a non-Z71. The skid plate will be necessary to purchase when doing the full conversion as it allows room for the 1.5" differential drop. The stock Z71 skid will hit the diff if re-used. Non-Z71 trucks will have the bolt holes drilled and tapped already there waiting for the skid. -The ZR2 transfer case skid is a partial direct fit. It will use (2) of the (3) bolts of the Z71 shield. If you are going from a regular 4x4 (non-Z71), you will need (2) 11518341 bolts (M10X1.5X25). The crossmember for the front skid holes will be drilled and tapped waiting for the skid. The rear of the skid will line up with the rear crossmember but you will need to drill and tap for (2) more of the same bolts, or alternatively like I did, drill through and use a through-bolt/nut/washer combo. I used a 3/8 stainless bolt with double washer and a lock nut. 2024+s may have the rear crossmember drilled/tapped for the ZR2 skid but need confirmation. -The only item not reused on the swap is (1) of the (2) small 10mm bolts that help hold the brake hose bracket on the knuckle for each side. This sounds critical but the bracket holds on to the knuckle just fine in the stock divots and using the singular 10mm bolt. You can ziptie or figure out a way to secure the un-used top hole but the ZR2 knuckle is not drilled and tapped for it's usage in that spot. Use Loctite blue (low strength for future removal) on the singular 10mm bolt if worried. -There is two un-used bolt holes drilled and tapped on the UCA. These are for the routing of the 2024 brake lines that allow room for the DSSV. If you are converting a 2024+ over to ZR2 suspension, you may end up using these with your stock stuff and the above brake bracket bolt usage bullet point may not apply. -ZR2s run LT305/70R18 (34.8x12R18) stock. Numerous ZR2 owners have converted over to 37s without trouble. This will largely depend on your wheel offset. I'm using a GM 18x8 with admittedly unknown offset, I am running Nitto 37x12.5s (36.5 actual height) with very limited rub on the front wheel liner. I've trimmed a small lower section of the liner and no longer have rub there. I have a touch of rub on the sway or frame at full articulation and turn lock but nothing audible, dangerous, or impactful long term. Those with custom wheel offsets that push the wheel out a touch should have no issues. Right now I'm sitting at 43 5/8" from ground to bottom of upper fender lip and about 44.5 in the rear using the full front/rear swap. I have not dialed it in all the way yet with the keys...etc until after I add the steering stabilizer (good idea when using 37s). -Someone asked about using the e-Locker. This is likely a cost ineffective or impossible swap considering it is most likely tied into the BCM, ECM, and various other 4x4 modules. Just be happy with the good 'ol G80 that comes standard on all HDs. As far as fitting a unit in and somehow actuating it with something like a factory Aux switch? Well....get to experimenting. I'll try to add more info as I learn it.

There's no route to adding the spotter light still. The mirrors are broken up into pieces on parts sites but only sold complete. I did find the lights though and they have two blade connectors on the back. I had planned to add them and hot wire them to one of my Aux switches but that is a far down the road project. I would need a mirror panel without the blank. That should be like a $30 piece. Not about to drop $700+ on a whole mirror and start playing around. If there was enough interest one of the custom wiring harness people would probably cook something up like they've done with the K2XX trucks.

DO NOT buy the POS AC Delco locking one. Thing is so thin and flimsy it's a joke. Broke in my hand. Even when placed on the cap locked it could be easily pulled off. Saw a warning somewhere a time ago but didn't heed it. HEED THIS!

I think the L8P is using LT1/2 cylinder heads. The combustion chamber and valve details lead me to believe that. I'm not aware of any port or valve dimension differences between them and the L8T though. The CC size is likely just to bump compression on the LTs.

Every gear or only from 2>1? It's unfortunately "normal" for HDs to clunk from second to first due to crap trans/throttle mapping in the tune. However, I have a buddy that had a clunk on his 24 and also a surge when placing in reverse, forward...etc and the dealer is telling him its a trans module and that "3 other trucks with the same thing" came in behind his which I highly doubt since we haven't seen this issue online en masse.

The ZR2 transfer case skid vs the baby Z71 skid. In the process of drilling the rear holes. Going to use through+bolts and nuts. Initially was going to tap M10x1.5 threads for one of the unused front Z71 bolts and add another, but didn't have the right 8.5mm or whatever PITA metric bit. Fits on the 20-23 great, just need to drill rear holes.

The people who want boutique things like single cab short bed HD with roll up windows and tiny mirrors likely don't end up buying it new anyway. Same for the "they should put an LT4 in a Blazer"!, then if GM ever spent the millions to do it, they wouldn't buy it. Dealers work in volume and stats. Most of the admin there don't even care about cars and are not car guys and don't even follow the industry. People that frequent this site and GM Authority are often FAR more informed than the typical sales manager. People assume since they work there they will have all the inside info and special access to GMs upcoming....etc. They don't care. It's all just metal to move to them. They know what sells based on history. Loaded up expensive trucks sell. Mid trim trucks (LTs) mid trim CUVs....etc sell. En masse. Boutique stripper trucks and expensive toys like Camaro V8s don't move the needle for them.

Tried a GM damper from a 2010 model a year before they discontinued it's use. Too short. Minimum collapsed length needed 14.25" & minimum extended length needed is 22" from my measurements.

Found a lower duct. Out of stock everywhere except a single dealer (tons of dealers around here). However, I doubt they have this "in stock" on the shelf. It let me order it though even though dealers less than 10 miles away it would not. GM parts research and ordering is such a laborious and confusing mess. Edit: I'll be darned. Was on the shelf I guess. Got a ready for pickup email lol. Dunno why they would have that laying around, but there ya go. After some tail chasing and gathering from 3 different sources, I've got everything ordered. Beyond what may be required to mod the airbox to TB connection, and relying on those ducts coming with the insulators and drain plug attached, I'm all in right now at $598.21. Compare that to the unreleased GM version at a discounters listed price of $809.68 pre shipping ($995 MSRP). If I can get this all to work I'll post a list of exact parts needed for the full swap. $600 isn't chump change to spend on a non-performance adding intake but at least I won't be embarrassed by the Toyota-like giant fake hood scoop any longer (barring that all this works!).

Since when did not getting all the coolant out of the head bolt holes on aluminum blocks become a "new" problem? Every shade tree worth his salt knows to get those perfectly dry or you'll crack the block torquing the new stuff down.

I think money might saved on the vent with some elbow grease. If you look close between the closed and open on the back, it looks like the closed could be an overlay fastened to an open one. Might try to chop mine up with a Dremel or blade in the front to open it vs spending over $150 on essentially what I have already. If I mess it up, oh well I needed to get one anyway. Those bolts listed are outrageous at $10-14 each and some sites say unavailable. I'm going to try some Amazon ones that are a touch shorter. GM uses zinc M6x1.0x30mm. I got like 20 of them dog nose with the washer on them like stock for peanuts in comparison, although they are M6x1.0x25mm. Also the nut retainer things they screw into. So far with the bolts/nuts, hood blanket, push pins, air box, and front duct cover thing I'm into it $206.05 with 15% off and everything but the Amazon bolts/nuts shipped to a dealer to avoid the massive shipping costs on the various discount sites. The scapped OEM version of this posted by newdude lists for $800+. If I can mod my stock hood vent, get the airbox to sync up and collect the main and upper duct I could get this done for half of that potentially. Stay tuned. Edit: After looking at my vent from the front up close I think it would be too much work to cut clean. Sickening to spend $112 + shipping on a new one but it is what it is.

The nature of the design is really that good on the L8T though. Isolated from everything else, in its own sealed air "tray" at the leading edge of the hood, direct shot to the sealed air box. I think the scoop is for the demand of extra air needed to feed the 900+lb tq of the big D. Also because it's a sales gimmick in a very competitive market. Gas trucks are mostly fleet purchases. Cost savings on the hood stuff over 100s of thousands of trucks is a big deal and fleets don't care that it's not there.

I wonder what's different between the one quoted and the chrome diesel one? The diesel one (84520314) is almost $47 cheaper. I remember waiting in limbo for the ZR2 knuckles to come back in stock. Looks like the same thing will be happening with the upper and lower duct.

This is gold. Thanks. Can you confirm how many insulators (look to be spacers for duct to hood) are used or if they come with the lower duct?

I agree the stock setup is great. This mod is more about OCD about fake scoops and wanting to mod for the sake of modding. I don't have the luxury of playing with LSx cars or Chevelles anymore like yore so this truck is scratching the itch. As far as air packing, keep in mind the engine is a large vacuum pump and will suck in what it needs regardless of low pressure zones...etc. Stock airflow and IATs are more than adequate. However, I am excessive by nature. My truck is on ZR2 suspension and 37s to haul sailboat fuel.

I'm going to start ordering some parts and take a blind shot. The lower intake tube is brutal with shipping and would be nice to buy on parts.gm and shipped free to dealer but is out of stock. [EDIT]Intermediate tube from near headlight to front of box is different between gas/diesel]. Lower tube on parts.gm also shows that it may come with the drain plug already attached so I may hold off on that. Part 5 is listed as the duct insulator but parts.gm shows it coming two piece and one of them looks like part 6. Also they look on the diagram to be part 9 and 10, so order two? I'll need help identifying parts 2 and 14. Parts 4, 8, and 13 are bolts but would be nice to get the exact PN. 3 is likely retainer 11611677, and looks like maybe need (9).

I would believe you because you're you lol. Are you able to hit up GM EPS and break down that parts diagram for us? Thanks

I'm ready to dig into this a bit further and get as much info sorted out as we can. Most people end up just putting a light bar in the scoop on the gas trucks. In the spirit of OCD and hating non-functional scoops since way way back, I'd like to take a crack at solving this puzzle. So far from what I've gathered, L8T and L5P use the same physical hood PN. The air inlet area around the top of the radiator looks the same and feeds both filter boxes by the passenger side headlight area. It "looks" like the only real difference is the hood insulator, some type of plastic plenum that directs air into the top of the L5P box that sits between the hood and insulator, an open scoop PN and some bits and bobs. This looks very moddable. I'm not aware that L5P uses any type of electric actuators or mechanical modulation to shut off flow during moisture events and may just rely on mechanical drainage (holes). Part numbers found so far (for 20-23): 2020-2023: L5P hood insulator: 84182769 L5P Silverado hood vent (custom/WT), black: 84520315 (midnight/carhardtt/Z71 plus), black: 84589745 (LT/LTZ/High Country), chrome: 84520314 L5P airbox: 85614333 In hood: L5P front air intake duct: 84684674 L5P rear air intake duct: 85126004 L5P intake drain hole plug: 84598171 L5P air duct insulator: 84358112 L5P air intake duct cover (needed?): 84496061 Not sure how many other bits and bobs are needed. I can find a parts explosion but have to search for the parts independently on parts.gm then look at the diagram and GM parts direct and go back and forth. Non common detailed GM parts are notoriously hard to search for. Any insiders like newdude out there? Can you dissect the parts explosion and list what is needed for this swap? As far as the airbox to throttle body connection I assume the connection from the airbox to TB doesn't like up perfect since its a rigid plastic tube. However, that can be dealt with using some malleable intake tube and clamps. I may also just go to the S&B L5P intake for this and mod the tube outlet to work. Some of this stuff is reasonable as far as cost and I'm willing to throw some coins at it to get it functional. The intake air temperatures will surely be mint although I know it's not going to give it any power boosts (that is until you start adding cam/exhaust/blower/tuning so don't be so hasty to think its a wasted mod). Any help on this topic is appreciated. Fake scoops belong on new edge Mustang GTs and Tacomas. Blasphemy on a GM product.

Ride is softer for me because I went from concrete POS 31" Firestones to 37" Nittos with 30% more sidewall. Still an HD truck. Still feels most things in the road. Even with DSSVs I doubt it softens up more. People that say they ride great are probably justifying their purchase in their minds. It still has a 3,500+ lb payload rear leaf spring that has to compress before the shock even thinks about controlling rebound. The OP that started all this was deep into changing brake lines and all that for the DSSVs. Dunno what happened with that. I still think for the same cost and likely better results King remotes that are at least rebuildable are the more prudent route. If I had a factory ZR2 and one of those leak prone DSSVs crapped on me I'd be trying to sell the other 3 and go to Kings before I spent another $800 for a single shock to maybe make it to 50k. That's just my $.04 (adjusted for inflation).