Supercup

Here is a dyno for 6.2L from Whipple website - 160 ft. lbs. +/- and 120 hp +/- 5.3L - 167 ft lbs. +/- and 121 hp +/- link: https://whipplesuperchargers.com/index.php?dispatch=products.view&product_id=522

Stock 18" OEM wheels have 26MM offset- which is about 5.50" back spacing on a 9" wheel - you need 4.5" backspacing on wheels to clear the tie rod. That is about <12> MM - I had Method 18x9 with 18mm offset (5.25" of back spacing) and we thought it would work - it did not clear tie rod - had to add 1.25" of spacer and wheel lug extensions to make it work and it just clears. Not ideal, but works for now - plan to either get 20" or <12> mm 18 inch soon so I can clear without spacers and lug extensions and add larger tires. With 20" wheel you don't have same issue as the tie rod will clear - albeit it is inside the wheel radius.

Know how you feel - at 10k my 2019 was also flawless - and it was all done! Hated to give it up. But when I found the exact same truck (sans the painted wheel arch flares) with all options I wanted + tow mirrors I figured it was worth reaching out to dealer. Mine was leased so I emailed dealer you take my lease back, and I will lease the new one, drive offs only. GM called me, said ran my lease, payoff was $52.9k, they would take it and lease new one to me for drive offs of $1,280 and $731 a month payment including tax. My 2019 was $750 per month. The $1,280 included the 1st months payment of $731 - so drive offs were $559. I said ok - they delivered the truck to my house that night and took mine away. What I gave up on 19 was Ready Lift SST 2" level kit - which cost $915 installed - but I was not happy with the CV angles or the fact you can't use auto 4WD with that level kit (did find out till after) - so it was cost I did not mind giving up. New truck got 2.5" BDS lift - better all around (cost a lot more, but worth the $$). So now I feel like I have the best of all worlds! If you get the right deal - you will not regret the tow tech or the big mirrors! The updated visibility is awesome.

Hope that works out for you, that would be a great! No dealer near me seemed to have a clue on how to approach this or want to touch it. Great addition for towing!

Do a search on this topic there are a few very extensive threads on this topic - including a step by step wire hook up and what you can get to work and what you can't. I talked to multiple S. Cal dealers about doing the switch - most said it could not be done. It can be done, but you won't get all the features you would it ordered from Factory. Only dealer who would actually quote me the swap wanted $2,000 for a $290 factory option and then when coupled with advanced tow in the tech package you get all the towing camera features, which is a great feature for towing. I ended up trading in my 2019 AT4 for a 2020 AT4 with tow mirrors and advanced tow. I got all the factory features and it only cost me about $600 to do the truck swap, so overall a great option, as I went from a 10k mile truck to a new truck with all the features I wanted. Good luck with getting this done, it is well worth doing as the visibility around an enclosed trailer is so much better, add the cameras down the side of the truck and trailer, along with the see through accessory camera and you have a very good and safe towing package. 2019 without 2020 With Tow Mirrors Tow Mirrors

Post pic's when you get it - looking forward to seeing it with 35 x 12.5's!

I had a shop recommend the sumo springs as a "next" step, after E rated tires - I think with WDH and sway control I have what I need for loads I am hauling - up to 9,700 lbs with trailer and 2015 Z/28 inside. D or E rated tires will be in my future as I replace the stock C rated goodyear duratrac's on my AT4 with something larger. I would take it step by step - do one thing - see how it is - add the next piece then see how it is. At some point if you have to keep adding you may have the wrong truck! The 1500 series should be good to go for up to 10k with 1k in tongue weight. For me if I were towing 9k plus all the time i would move up to 2500 diesel truck again, but for the loads I tow (4,500 - 9,700) the 1500 is fine and it offers a little nicer everyday driver when not towing than the 2500 - not to mention it is $20k less expensive!

I looked at Method Con6m us that what you have on order - or is it a Icon suspension with Methods? If you ordered the Con6 it does not look like you can order the -12 mm offset (4.5" of backspacing) 18 x 9's - only the 18 mm (5.5" backspacing). If you consider other Method options the -12mm with 4.5" of backspacing will give you more inboard clearance and better overall flexibility to fit larger tires. FYI stock AT4 18's are 26mm offset - so 18mm does pick up some inboard room - but the -12mm picks up a lot more. I had the 18mm with 5.5" of back spacing - with Ready Lift 2" SST kit with UCA's on my 2019 - I had less than 5/8" of clearance to my 275/65/18 - I could not have fit a 295 - a 285 would have been very close. With stock upper control arms you pick up about 1/4", so a 295 likely would just fit. I am using same wheels on my 2020 - when I added BDS 2.5" lift kit - the tie rod hit the wheel, so I had to add 1.25" spacer and lug extensions to make it work. Backing up at full lock I have some minor rubbing I have not sorted yet. So I am now going to swap to the -12 mm with 4.5" of backspacing so I can have more tire options and clear the tie rod without the spacer or lug extensions. I have Method NV's. Good luck with you updates - should look good. 2019 with 18mm offset Method NV 18x9 - inboard clearnce stock Goodyear Duratrac - 275/65/18

I have 2020 AT4 (had 2019 AT4 before) and tow a 24'' Intech enclosed trailer. No questions this truck is sensitive to tongue weight - I have found different settings on WDH for loaded or empty will change how it behaves. Too much tongue weight and it will give you a little sway. In addition to WDH I run a sway control bar on trailer that attaches to truck hitch as well. Have had good success with this set up on past trailers and with this one as well. My trailer will drop @$$ end 2.5" without WDH and about 1" when it is set with some tension. I have bars rated at 1,500 lbs each (this is important, as if you have 800 lb bars, that is all the weight you can shift to front wheels). To get serious tension aon WD bars a good trick is to hook up, then use jack to lift the back of the truck up above level - this will allow you to catch lower chain links and add to tension and throw more weight forward. I also find that this truck sucks into passing vehicles, but mostly big trucks or motorhomes - not much on cars. I do think it is something you get used to and notice less as you tow more. I also have the advanced trailering package and tow mirrors on my 2020 (why I switched from 2019) and find the overall package is awesome. The mirrors and camera views down the side and out back make trailering so much safer and easier. I knew it would be a plus, but had no idea how much better it would be. I added a photo of the sway control set up I have (not same brand, but same set up).

No Max tow option for AT4's - so all have 3.23's

10-11mpg towing a 5,000 box through the wind is pretty good. I have 2020 AT4 and had 2019 AT4 before, both with 6.2L - towing my 24' Intech empty I am at 4,600 lbs +/- - at 60 - 70 I get 9-10 mpg. at 8,000 lbs I get 8.4 - 9.2 pending the number of hills. So you are a little better, but not as much as you might have hoped. Regardless a very nice set up! Can't believe you got 30 mpg - I have never seen anything north of 21 in mine. For comparison my 2019 over 10,500 miles averaged 14.5 mpg of mixed city and freeway driving, with about 2,500 miles of towing thrown in as well. Best tank was 21 and worst at 8.1 towing into the wind.

Specs for my tire are 32.3" tall - A BFG K02 35 x 12.5 x 20 - 34.5" tall so if all else is equal - you would be 2.2" taller than mine - so 80.25 + 2.2 = 82.45" +/- tall - when comparing to mine as is. So closer to 4" of total height increase over where you are now (82.45 - 78.5)

James Here is photo on level ground - no trailer - there is some rake. Other Information Height - ground to top of shark fin on roof is 80.25" +/- and 88" to top of antenna with 275/65/18 tires - 2.5" BDS lift on top of 2" factory lift on AT4 - so figure you need 81" minimum to clear your gargage door or header

275/65/20 is standard sized on 20" wheels from the Factory with AT4 and Trail Boss - I have AT4 - plenty of room - don't think the 2" of Factory lift makes any difference in how they will fit.

Hi, I am wondering if you got the large skid plate up front to go on, without removing the air dam? Shop that installed my lift said on AT4 had to remove all the front air dam stuff and they did not recommend as if done, it created a lot of wind noise, that customers were not happy with. So they gave me the skid, not on the truck. Can you take a picture of your front skid plate underneath and show how it was attached by the bumper - I like the look so am interested if you figure out how to install and keep the front airdam?

I will try to get a pic on level ground without the trailer - there is a slight rake, but not much. I went with 2.5" (4.5" overall) instead of the 4" (6" overall) as I trailer a lot and wanted to keep decent mileage and good trailering characteristics. Seemed like the sweet spot. Currently running 275/65/18 stock Goodyear Duratrac wheels. With 2.5" lift I think 33/12/5/18's are as big as BDS recommends on 18's - you can go to 35's with 20's, but I don't want 20's.

Other Photos 2019 with Trailer 2020 with trailer - tow mirros and accessory cameras added - big plus - way more visibility and saftey when towing BDS Stuff

I have a 2020 AT4 Carbon Pro and added a BDS 2.5" lift kit with 2.5" Fox DSC coilover front shocks, Fox 2.0 rear shocks and 3" rear lift block (replacing factory block). I had a 2019 AT4 Carbon Pro with Ready Lift SST 2" level kit and RL UCA's. The look is similar, but the performance is in another league with the BDS kit. Most significant improvement is the "angle" of the front axels - I have posted photos below of the RL level so you can see the angles at the CV boots, pretty extreme, versus the BDS lift kit with drop bracket, which leaves the axel basically level - alllowing a lot more flexibility in articulation. Ride quailty is excellent, but it is stiffer than the stock Rancho momo tube shocks, which are quite plush. The stock Ranchos are good for about 5 mph in any kind of offroad terrain, the BDS is much more compliant and offers far better offroad performance. With the DSC adjustment of the front shocks I was able to smooth out the ride to be similar to stock, very comfortable, yet more composed and in control. A litte more steering effort with the BDS as well - both on same wheel and tire package. Only issue I ran into is I have 18" x 9' Method NV wheels with 18 mm offset (5.75" backspacing) and they interfered with the BDS tie rod. They worked ok with RL SST kit - but were very close to the upper UCA but worked. In both cases the Method 18" x 9" NV's with -12 mm offset (4.5" of back spacing) would be a better choice. I will switch to those once I am ready for larger tires, for now due to wheel issues I stayed with stock 275/65/18. With RL SST kit there was maybe 5/8" of room to the tire, so very limited room for a larger tire, whiich 18mm offset wheels (stock 18's are 26mm). The BDS kit has a ton of inborn room - a few inches or more, so no issues there. With BDS and 18mm wheels slight rubbing when backing up at full lock. Here are some comparison photos. 2019 AT4 Carbon Pro - Ready Lift 2" Level 2020 BDS 2.5" Lift Kit 2019 RL SST 2" Level - CV axel Angles - level ground 2020 BDS 2.5" lift Kit - CV axles "level"

Traded 2019 for 2020 - to get trailer tow mirrors and more cameras to view around the trailer - same options as 2019. Added BDS 2.5" lift with Fox Coilovers with DSC in front and 2.0 Fox's in the rear. Very happy witha the outcome. Had RL SST 2" level kit on my 2019 with RL upper control arms. Shaft angles were too extreme - with BDS they are basically level with diff drop bracket - much better set up. Only issue I had is my 18x9 methods are 18MM offset (5.75" backspacing) and that interfered with the tie bar - so had to add spacer for now to make it work. Better wheel set up would be Method 18x9 with <-12> mm offset (4.5" of back spacing) - that would eliminate the need for the spacer. when I get bigger tires I will make the switch. RL SST 2" level kit with UCA's - 2019 AT4 BDS 2.5" lift with Fox shocks on 2020 AT4

Here is window sticker with what mine has so you can see exactly how they word it.

Here is photo of my 2020 AT4 - tow mirrors and trailer. Tech package included Bed view camera with 2 trailer camera provisoins (plugs above trailer plug for accessory cameras) and outside trailering mirrors - when combined with Tech package when trailer is plugged in the cameras in the side mirrors can be used for viewing down side of truck and trailer when driving. The accessory cameras - one for back of trailer to create the "see through" effect and a 2nd one if you want inside your trailer to see what is going on with cargo inside. The accessory cameras have been backordered - I am still waiting for one to go on the back, but the tow mirrors work great. I looked into adding the tow mirrors and no dealer near me in S. Cal could figure out how to do it, plus it was going to cost way more than getting the from factory on new truck. So if you want that get it in your deal and make the dealer do it for you. It can be done (another thread on that here), but it is not easy. The slip overs mirrors don't work well - I tried 3 different ones for my 2019 - and none of them helped with visibility much - the mirror were to small or low quality and don't go out far enough. Finally I started looking for a 2020 with to mirrors. Found truck with same options, fair deal and made the change - was a very good decision. The 2020 is so much better with cameras in mirrors that see down the sides and the dual mirror, plus the mirrors extend out - there is no comparison on what you can see and how much safer it is.

If you tow 30' trailer - be sure and get the Trailer Package with tow mirrors - you can't see arount an enclosed trailer with standard mirrors. The trailer package with side and see through cameras is awewome - I had a 2019 Caron Pro AT4 without trailer mirrors or two cameras - traded for a 2020 Carbon Pro AT4 with trailer mirrors and trailer camera package, the difference when towing in visibility is night and day - so much safter and better visibility. Love the 2020 with the trailer package! Good luck finding right truck. John

First we are not in 1965 - but sure wish we were for gas prices at $0.20 per gallon! For those of us who tow with our truck we want a reasonable range - at 8 mpg towing you are looking at 200 miles of range +/-, that is simply not enough. A 36 gallon replacement tank would get you to about 300 miles - which is bare minimum. 400 miles would be ideal, just like the truck not towing. A Jerry can requires a stop and fill, which we are trying to avoid, to keep our time of travel to a minimum. We could buy a diesel and get more range, but we don't want to drive around a 3/4 or 1 ton truck everyday and don't tow enough of a load to warrant the added torque of the big trucks diesel motor. The Duramax for the 1/2 ton does not get any better mileage towing a 8,500 lb. enclosed trailer like I do, so that offers no additional range and worse performance on the street. So end of the day it is all about how you use your truck. I like driving a 1/2 ton everyday for ride quality and size, I like having V8 rumble and the performance that goes with the 6.2L and 10 speed. I have no issue paying for gas or accepting lower mileage to get what I want. Only thing I can't get is "decent" range when towing. That is the one compromise this thread is trying to address. GM won't be offering a larger tank, due to cost to certify. Most aftermarket tank builders won't touch it due to EPA and CA CARB rules and extreme penalties for messing with the emission, which the gas fuel tank is a part of. So for now we will live with poor range and jerry cans, unless we can find an alternate solution. I am working on tank on passenger side that will transfer fuel to the main tank. Hoping to add 20+ gallon tank there with fuel fill just like the main tank and call it a day at 46 gallons total. Now just finding someone who can do that and make it safe is the challenge.

Looks good!

Had Firestone airbags ready to got in. But dedided to trade truck in for a 2020 AT4 Carbon pro with trailer tow mirrors and aux camera tech - which my 19 did not have (either). So I returned the airbags. Went with load leveling hitch for trailer and that seems to be working fine. For the 2020 I am doing BDS 2.5" lift with fox 2.5 DSC coilovers up front and 2.0 fox shocks in the back. That goes in next week. Once that is done will decided if I need airbags or not. But liklely will not be adding them at this point.