Engine Swap: LT5 or Built and Blown 6.2

Descartian · January 6, 2021

Hey there guys,

I just picked up a 2020 Sierra 2 door as a project truck. Its heading into the body shop early February for some mods I'll disclose later. I'm looking to hotrod this truck.

My question is this, should I go with a factory LT5 at 755 horsepower or should I go with a custom built 6.2 with a blower and push it up to 800-850hp? My attraction to the LT5 is the "stock'ness" of the crate motor.

Thank you for your opinion.

Edited January 6, 2021 by Descartian

BluegrassMotorsport · January 6, 2021

I think this will be hilariously excessive and I'm subscribing to follow the build. This is amazing.

LT5 please.

CamGTP · January 6, 2021

Do you live in the middle east or is it a long bed north american model?

Descartian · January 6, 2021

Well technically they sell the 2 door regular bed versions in Mexico too.....

That's the part of the body shop ill get into later but its going to be a 2 door with a short 69" bed. (and 4x4) and I'm in the States.

lebag335 · January 6, 2021

LT5

KARNUT · January 6, 2021

I’d go the blower route. I’ve done both. If it’s a daily especially. You have the option of pulley changing to fit the mood. Or tooling around in a tame vehicle if you just want to cruise. I’ve gone form 6 to 12 lbs of boost in ten minutes with a pulley change. In my case 100 HP.

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Steve-2019 · January 6, 2021

LT5

Enough · January 7, 2021

Looks like a long bed regular cab is about to be shortened......really shortened.

Sounds like a fun project !

Descartian · January 7, 2021

28 minutes ago, Enough said:

Looks like a long bed regular cab is about to be shortened......really shortened.

Sounds like a fun project !

Yes, yes and yes.

Talked to a well respected speed shop today. Initially wanted me to keep the original 5.3 and have it worked over with a supercharger. Said I could easily get 500rwhp out of it but after talking about future needs the 6.2 will be a better fit, even seemed excited about putting the puzzle together needed to adapt the LT5. I’m leaning that direction with some mods (headers/cam/etc) and port injection.

if you have a good argument against it let me know.

CamGTP · January 7, 2021

All I know is that is going to take a wizard or maybe a miracle to make all the computer stuff work if you keep factory computers. The 2019+ stuff is so limited and there is zero TCM support with HP Tuners.

Obviously would be different if you are just using this as a body/chassis and went with an older PCM/TCM or were doing a stand alone system with digital dash and yadda yadda.

Enough · January 7, 2021

I had a 2016 Regular cab short bed with a stock 5.3 and 3.42 rear end with factory locking diff for a couple of years. In the rain it was like driving a go cart. You had to get used to driving sideways.

Lopping another 10-12 inches out of the wheelbase and doubling the horsepower should make things even more interesting.

I would love to see pictures of the shortening process. Many years ago my Dad and I shortened an F-250 crew cab 4WD down to a regular cab short bed. The frame had to be shortened 33-1/2", the brake line had an extension in it that we took out and connected the line back together, there wire 6 wires that had to be shortened, and the driveshaft had to be shortened. Things were a lot simpler in 1979 !

Descartian · January 7, 2021

9 hours ago, Enough said:

I had a 2016 Regular cab short bed with a stock 5.3 and 3.42 rear end with factory locking diff for a couple of years. In the rain it was like driving a go cart. You had to get used to driving sideways.

The auto 4wd should help with this. I also have a couple other vehicles I can drive in the rain that are more sure footed.

9 hours ago, Enough said:

I would love to see pictures of the shortening process. Many years ago my Dad and I shortened an F-250 crew cab 4WD down to a regular cab short bed. The frame had to be shortened 33-1/2", the brake line had an extension in it that we took out and connected the line back together, there wire 6 wires that had to be shortened, and the driveshaft had to be shortened. Things were a lot simpler in 1979 !

The shop that is going to do the work has done one before (the owners truck). They take 6 or so inches off the back of the frame then cut an existing weld under the cab and take the rest of the material out of that area and reweld it. Brake lines get shortened, fuel lines go to braided soft lines, parking brake lines moved l, bed and can frame mounts relocated and a new shorter driveshaft (also beefed up to take the increased HP). And then the 4 link coil over rear suspension which for the 6” rear drop will most likely require a frame notch.

Descartian · January 29, 2021

The further we got down the LT5 route the harder it looks like it’s going to be. Also all the accessories will have to be for a ZR1 which means $$$$ at every turn. The engine computer is $4k alone.

Going the built and supercharged 6.2 route.