Trail Interview: Meet Jason from RSG Off-Road, and the T40R V8 SAS Build

RSG Offroad T40R - 5th Gen 4Runner SAS Build V8 Swapped and Supercharged

Meet Jason from RSG Off-Road and his T40R: A Straight Axle 5.7L V8 Swapped and Supercharged 5th Generation Toyota 4Runner

This interview has been in the works for quite some time. We brought up the idea long before Jason (the founder of RSG Offroad and RSG Metalworks) swapped a 5.7L V8 into this beast known as the T40R. Back in 2018, when we first featured their rock sliders, we brought up the idea of an RSG Offroad interview and overview on the T40R. Jason was busy, I was busy, and like most important things in life, it just got pushed to the side.

Since 2018, Jason has been busy building both of his businesses and equipping the T40R with a 5.7L V8 Tundra engine paired with a Magnuson Supercharger. Yes, you read that right. This 5th Gen 4Runner is not only running straight axles on 40″ mud terrains but also features a blown Tundra V8.

We finally got to catch up with Jason at his shop in Lakewood, CO, to see the T40R… spoiler alert, it was so freaking rad!

First, let’s back up a bit.

We had a trip planned for Ouray and Telluride with Konrad from but with plans to also stay in Denver before we headed down. While I was in Denver, I wanted to at least find the time to stop by RSG Offroad and say what’s up.

Well, we ended up having too much time on our hands because our 4Runner delivery was delayed by 4 days. I was literally stuck in downtown Denver Colorado for 4 days waiting for my 4Runner to get delivered. With that said, Jason stopped by my hotel, picked me up in the T40R and we hit the streets on straight axles and a blown V8. It was loud, very very loud.

This 4Runner is Insane!

Dude, this truck is freaking gnarly! It’s so incredibly loud.

The 4Runner body was not designed to contain the sound level that a supercharged V8 pushes out. It’s so loud and aggressive you can literally feel the sound in your body. It’s pretty great. My eyes were wide open for about an hour straight. I was just in pure awe of what Jason has created. It’s like an evil villain and Jason started drinking some beers, had a few too many, and the T40R was created. This thing is a straight monster!

The skill it takes to extract an entire ECU, all the wiring harnesses, and the engine from a Tundra, and then swap all that over to a body that’s 20% smaller – all while making it look factory on the inside… is crazy impressive. This dude can seriously build a 4Runner.

I laugh thinking about that thread on “what did you do to your 5th Gen today”… oh just swapped a V8 and then supercharged it. No big deal.

Jason actually started a thread on a while back but most of the images are broken, and if there’s one thing you can count on with forums it’s broken images. We’re not restoring that build thread here today (maybe one day if you guys want us to), but instead sharing a basic interview with the man himself along with a ton of rad T40R shots.

Picture Credit: Most of these photos were shot and edited by RSG Metalworks employees and fellow Toyota owners; David Todd aka @TrailboundT4R, and Ryan Strate aka @RyanStratePhoto. Both of these guys are a pillar part of the RSG family and it shouldnt go unoticed.

We Found Some Time

RSG Offroad Shop Lakewood Colorado

We were able to roll through RSG Offroad and the RSG Metal Works shop out in Colorado this last month and I can honestly say Jason is one of the coolest people I have had the pleasure of meeting. His shop, his family, his team – everyone he works with was just genuinely cool and incredibly humble.

Jason and his team at RSG Offroad run a pretty successful Off-road service and installation shop in Lakewood, CO. They specialize in pretty much everything offroad; parts, sales, service, suspension installs, tire/wheel mount and balance, body mount chops, custom fabrication, switch wiring, lightbar wiring, armor installs, and much more. If you’re located in or around Colorado and need a dependable and reliable shop, look up RSG Offroad.

We spent the day with Jason and his crew while I waited for Jade (our 2016 TEP pictured above) to get shipped in from California. It was really cool to get to see both of the RSG shops and I was honestly incredibly impressed with what Jason has built. From his 6-bay service and installation shop with a parts showroom (RSG Offroad) to a full-blown team of fabricators in another (RSG Metalworks) – Jason has built quite the brand.

While we’re talking about the brands, you might be asking yourself what’s the difference between RSG Offroad and RSG Metalworks? RSG Offroad is their service and installation shop with a parts showroom and RSG Metalworks is the company that produces all their branded armor; rock sliders, skid plates, etc.

Without any more, let’s jump in. 

I am incredibly hyped to finally bring you the long-awaited RSG Offroad interview and T40R build overview.

When and where did your automotive life start?

Jason - RSG Offroad

When I was a kid my father, Craig, restored Early Ford Mustangs and Broncos in beautiful Wheatridge, Colorado.

The first vehicle that I owned was an 84′ Ford Ranger, then a 1987 Honda Accord, and then a 1991 Acura Integra with a spoon engine from Harry’s. I worked as a technician for a couple of car audio and performance shops in Colorado over the years with heavy experience with engine swaps, rebuilding engines, Forced Induction, and hanging with people that did things to cars that nobody else had ever done, mostly in the Import Tuner Scene.

Before there were security cameras on everyone’s houses and inside vehicles, everyone wanted a car alarm and remote start. I started a mobile business with me as the only employee and drove around to people’s homes and offices and would install the systems for them at their location…

RSG (Remote Start Guys) started in 2012 in a 2 bay warehouse in Wheatridge and we specialized in remote starts, automotive repair, and installing suspension systems on Jeeps, Dodges, Fords, and some Toyotas.

And then RSG Off-Road & RSG Metalworks Started?

RSG Offroad - 4Runner V8 Swap & Straight Axle Swap

Around late 2014, RSG Offroad in Colorado started building Toyota trucks and providing installation services built out with Bilstein, KING, BDS, FOX, SPC, and other major brands. As time went on people started to request more parts such as armor and RSG was reselling other armor companies parts such as RCI, Hefty, CBI, C4 Fabrication, and others.

In late 2017, RSG started building their own armor, including their first set of rock sliders to fit the growing demand for the offroad community. This new line of offroad parts would operate under the RSG Metalworks brand. Today, RSG offers a streamlined fabrication production line including rock sliders, skid plates, and electronic parts for many different Toyota and Lexus models.

Why 4Runner’s?

RSG Offroad T40R - 5th Gen 4Runner SAS Build V8 Swapped and Supercharged

The 4Runner has been a staple in the SUV market for years and I always felt it had a ton of potential as far as reliability but the off-road ability, power, and stance were lacking. We enjoy pushing the vehicle’s limits and learning from them.

The first time we crossed the 5th Gen “1st ones to do it” line was with Abby’s 2014 Trail Premium with KDSS that we installed a Modified Fabtech Toyota FJ 6″ kit with 35’s. We machined the knuckles to fit the 5th gen 4Runner calipers and machined some parts in house to adapt the KDSS system. Prior to that, we had a 4th Gen 4Runner v6 with a 3” kit with 33’s.

Solid axle build list from 2017

RSG SAS V8 4Runner

  • Front Axle Housing from Spidertrax with Tacoma Currie Rear Axle Assembly with Chromoly axle shafts and Warn hubs 1st Gen Tundra Disc Brakes.
  • Custom 3-Link in the front built by Justin Mildenberger who was an employee of RSG for a number of years (the same guy who built the All-Pro Black Betty Solid Axle Tacoma and @4RunningMutts on Instagram).
  • Full Howe hydraulic assist steering custom built with the pump, steering box, ram, and cooler.
  • Rear Housing – Ford 9″ size fully built Tacoma Currie (Currie Enterprise) with adapter kit for the brakes
  • Rear Currie Antirock Swaybar
  • Gear Ratio  5.13 front and rear
  • Custom driveshafts built with a larger U-Joint and larger diameter shafts
  • Dual Cases (Tacobox)
  • Magnuson Super Charger
  • 12″ KING Coilovers (12″ travel on all corners) with remote reservoirs all the way around
  • 40″ Toyo MT 40X13.50R17, 17″x8.5″ Trailgear Beadlocks with -18 offset
  • Custom RSG Off-Road hybrid front and rear high-clearance bumpers
  • Angled RSG Off-Road Rock Sliders
  • Hefty Fab Gas Tank Skid Plate
  • Ipad Converted Dash Kit
  • Later we installed the Kenwood DMX1057XR

Then you bought a Tundra for an engine swap?

Swapping a V8 Into a 4Runner

Everyone always asked what I’d do next to the 40 and I always said “Tundra 5.7 swap”

So one day in early February 2021 I found a donor Tundra on CarPart and bought it!  We drove that truck home, made sure it ran right and then pulled it apart.

The 5.7L V8 Engine Swap was from a 2013 Tundra. I started by removing the Tacobox along with other 4Runner parts pre-added to the truck during the SAS build-out and started getting into it. Everything was removed from the 4Runner aside from the suspension, the body, the frame, and both axle housings. The complete Tundra wiring harness, every  ECU/ECM, and basically all electronics from the Tundra were swapped into the 4Runner.

That includes the brake skid control, brake master/booster, body control module, 4wd control module, and other systems like the mobilizer, fuel pump module, all the emission-related and evap items were swapped, both air-injection pumps (which were coded out later) and wiring, along with many other parts. Additionally, a GX460 Radiator was swapped in. For the transmission and transfer case, a new cross member was built and Tundra transmission mounts were welded in. Finally, the motor mounts were cut from the Tundra and modified to fit the 4Runner.

Swapping a V8 Into a 4Runner

After the swap was up and running we had the exhaust done by a local shop and Toyota re-calibrated the ECU with Toyota supercharged TRD firmware so we could access the additional tables provided with that firmware with HP Tuners and then the Magnuson Supercharger was installed and the Tuning process began.

T40 Running the Quarter-Mile

For the Tuning we used Viktor G, you can find him on YouTube as “Viktor G”. If you want to see and hear another video clip, check this out.

What’s next for the T40R?

RSG Offroad T40R - 5th Gen 4Runner SAS Build V8 Swapped and Supercharged

The shops have been extremely busy this year and we have yet to take it off-road since the 5.7 swap so that’s what’s next. We need to get it out and play!

What’s your favorite mod on the T40R?

RSG Offroad T40R - 5th Gen 4Runner SAS Build V8 Swapped and Supercharged

My favorite mod besides the gobs of power honestly is the steering. The vehicle turns so effortlessly and easy makes it a joy to drive.

How much money do you have in the T40R… if you don’t mind?

RSG Off-Road T40 Build (V8 Swap 4Runner)

The amount of time exceeds the amount of money I think at this point.

Here’s a quick rough breakdown:

  • $40,000 Vehicle
  • $60,000 in Parts from the original build
  • $25,000 in Parts from the engine swap
  • $75,000 If you counted labor at $100 per hour we have roughly 750 hrs into it
  • $200,000 Rough numbers

What products does RSG Metalworks offer for the 4Runner?

RSG Metal Works in Colorado - Rock Sliders for Toyota

A few of the products RSG Metalworks Offers:

What products are next for the 4Runner?

RSG Offroad 5th Gen 4Runner SAS V8 Build

I don’t think we will add much to our lineup except for a rear skid option.

Your Favorite Trail in Colorado?

Offroad Trail in Colorado - Top 3 for RSG Offroad

It’s hard to pick just one so I’ll name a few:

  • Spring Creek
  • Wheeler Lake
  • Chinaman Gulch

Any Plans for new Toyota Builds?

Swapping a V8 Into a 4Runner

We will most likely do some crazy things to the 6th Gen 4Runner when it’s available.

If you could wheel anywhere, where would it be?

RSG Offroad T40R 5th Gen 4Runner SAS V8 Build

I’d like to spend some time in Baja California, Mexico.

Most Important Mod?

RSG Offroad T40R 5th Gen 4Runner SAS V8 Build (Rock Sliders)

Rock Sliders! I would recommend rock sliders because the last thing you want to do is tear up your new vehicle by sending a rock through your rocker panel. Most offroad version vehicles have factory skid plates so that’s better than nothing.

What’s your favorite Rock Slider you offer?

RSG Offroad T40R 5th Gen 4Runner SAS V8 Build (Rock Sliders)

I like the angled grip hole version with the powdered logo.

When are you launching that T40R hybrid?

RSG Offroad Hybrid Front Bumper on 5th Gen 4Runner

As soon as I get my life together. lol

Any RSG Off-Road Rear Bumper Plans?

5th Gen 4Runner Hybrid Rear Bumper (RSG Offroad)

Possibly, bumpers are heavy and a pain in the butt to move around and ship to people so that’s why we have avoided them in the past.

When can we expect a T-Case and Crossmember Skid Plate?

Straight Axle Swapped (SAS) 5th Gen 4Runner

My hope is later this year. Possibly at some point in 2021.

Will RSG plan on Diff Skids, LCA Skids, or Other Products?

Straight Axle Swapped (SAS) 5th Gen 4Runner

Anything is possible! It’s definitely something we’ve been looking into recently.

What’s next for RSG?

RSG Offroad T40R - 5th Gen 4Runner SAS Build V8 Swapped and Supercharged

We could possibly get into bumpers and are looking to expand from our current 5000sq ft building to a 10-20,000sq ft building.

Final Thoughts

RSG Metal Works in Colorado - Rock Sliders for Toyota

Well, after all that, now I want to swap a supercharged V8 into my 4Runner. And I want 40″ Toyo M/Ts, and I wouldn’t mind some full-width axles either. OK, I’ll just come out and say it, I want this entire build!! I don’t think I need to go into any more details on this amazing build. If you have any questions for RSG or the T40R, you can find them all over Instagram. You can follow all three pages for more on what Jason is up to and more of what’s to come from the RSG line of aftermarket parts and accessories.

Find RSG online: 

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1 year ago

Would like avenue to get expanded front fenders

2 years ago

Can someone please write the literal step by step on a sas? Just lay it out and outline the price. thanks,.

Allen Wheeler
Allen Wheeler
2 years ago

When is RSG going to start offing SAS V8 swaps as a service?? I actually found RSG on this site a few years ago and bought a set of sliders from an old post. THEY ARE STOUT! Love my RSG sliders.

Chase Waeckerle
Chase Waeckerle
2 years ago

I would like to discuss a custom Öhlins suspension in my opinion easily the top suspension brand on the market today. Can this be a feasible addition? I am very interested, the only other cars I would rather have would be a G class of which I have owned 3, 2 g550 bi turbos, and the G63 AMG with 50k in RennTech aftermarket upgrades, the old school Land Rover defender 110, and my current obsession the new Rivian all electric off-road SUV.

2 years ago

RSG is a top quality shop. I just had them install a rear Eaton e-locker on my 5th gen and it’s amazing. I’ve used it a lot since and flawless performance and install. It took me a while to even find the wiring for it due to how well they wired it up. Plus I have their rock sliders and they’ve held up perfect.

Dan Reebs
Dan Reebs
2 years ago

This was one of the best articles ever. Really enjoyed this build. They took it so far and I really love it. Nice job.

Stinky Pete
Stinky Pete
2 years ago

There’s a lot of first gen tacomas that could use RSG sliders.

2 years ago

Wow man this build is pretty sweet. “how much did you spend.. if you don’t mind” hahaha.

2 years ago

Man, what a great post!! Nicely done!

Kim Strothkamp
Kim Strothkamp
2 years ago
Reply to  JasonRSG

Is that a “peckerwood” hand jester in one of your pic?

Jason Sampson
Jason Sampson
2 years ago
Reply to  Kim Strothkamp

That’s the “look at this” and I have no clue why that photo’s in there!

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