Intro & planning post

[X-Factor]

First post. Long winded - don't TLDR me please lol.

As a kid I grew up with Suburbans - learned to drive on an 89 GMC Suburban that my dad bought new - only new car I think he ever owned, a 99 Chevy Sub shortly after (we needed both - big family!). Since then I've personally owned a 97 (?) Tahoe, 99 Chevy suburban, and in 2018 I picked up a strangely low mileage (comparatively) '06 XL Denali with every option available at the time - still have the window sticker too. Every time I've NOT had one of these trucks, I've regretted it. So, I will be holding onto this one until the wheels fall off...

I've driven it all over the east coast at this point, she's sitting at around 150k miles - truck has been flawless aside from those pesky 20" stock wheels leaking like a sieve. Annoyingly frequent cleaning job is required on them to hold air. Aside from that....she's been a joy. Paint is heat damaged, changer hasn't worked since I bought it but I've been too lazy to fix it (yes, I still use CDs). Wife has since crunched the driver side mirror which is cosmetic but annoying damage.

Also since I was a kid, I dreamed of shoving a big block into a Suburban and making it a sleeper truck. The 454 seemed like the pinnacle of power to me in the late 90s, so while that motor isn't on my radar anymore, this beast of a 6.0 seems like a good alternative. While it won't be a "fast" truck for these days, it could be enough fun for my midlife crisis. I had to replace my muffler a few weeks ago and it woke up the old me lol. I have a vision for this truck, and since I don't have fast cars anymore this itch might need to be scratched. I'm no mechanic, nor will I pretend to be one. Here is my plan, as I start to sketch out the path:

Power:
compression/sonic checks first
Intake
Headers
full exhaust
fuel system?
Tune - what is the move here?
I was told (and have seen here) to not open the block until its really necessary so no intentions there. Probably need to understand the upgrade path there as well.

Transmission:
Upgrade the 4L65E to 4L80E - no shifting issues but she's a little sluggish and I don't think will like more power.
Rear diff?
Not sure what all is needed here that makes sense....who is the best in this realm? I had reached out to Monster Transmissions but haven't connected yet.

Interior:
replace changer
slow project to turn interior into a sleeper cabin - long term project.

Exterior:
Swap the 20" wheels with 17/18s - anyone know the stock 20" wheel weight? Haven't been able to figure this out, would like to know so i can make sure I'm maximizing rolling resistance reduction.
Tint front windows
Bull bar
Probably respray the whole truck either the stock silver or a matte gray. Not sure.

Thanks for reading - she's an older beast now but man I love this truck...

 

[89Suburban]

Nice Burby! Welcome!

 

[X-Factor]

Nice Burby! Welcome!

Thanks man! Love that PPV!

 

[swathdiver]

Good plan. Those wheels were GM Accessories for the generation after yours, 2007-2013.

If you put the 4L80, then you'll probably want to change the gears to 4.10 or lower ratio.

 

[X-Factor]

Good plan. Those wheels were GM Accessories for the generation after yours, 2007-2013.

If you put the 4L80, then you'll probably want to change the gears to 4.10 or lower ratio.

Ahh good to know. They look good (better than the Escalade wheels - eww), but aren't in great shape now. Heavy and corroded sadly. Not wheels i would have chosen.

 

[X-Factor]

Good plan. Those wheels were GM Accessories for the generation after yours, 2007-2013.

If you put the 4L80, then you'll probably want to change the gears to 4.10 or lower ratio.

Looking at my build sheet from compnine it appears that the 20" wheels were factory. perhaps not THESE 20" wheels, per se, but my truck had them originally.

 

[SilverSport]

your Wheels are the optional 20 inch wheels for the 2005/2006 (at least) GMC Yukon Denali...sorry to read they are leaky
here is a pic of them on the cover of the 2006 brochure

https://m.media-amazon.com/images/I/610RgWjFJmL._AC_SL1000_.jpg

Bill

 

[Mudsport96]

Power:
compression/sonic checks first

Compression check is a good start. To sonic check the block it has to be disassembled so skip that

Intake

Tube or manifold? The stock truck manifold is about perfect for these trucks maybe the Trailblazer ss intake beats it some, but not worth the effort if you aren't going wild

Headers

If you go headers get long tubes, shorties don't give enough power back for the cost and work to do them

full exhaust

Will be required for long tubes anyway

fuel system?

Maybe new injectors but stock flow rate should support most of what you do.

Tune - what is the move here?

A tune on a stock engine is worth some, but if you do headers you will want to get one. Contact Blackbear Performance they are a sponsor here

I was told (and have seen here) to not open the block until its really necessary so no intentions there. Probably need to understand the upgrade path there as well.

At this age, I would consider replacing the oil pump Oring on the pickup tube. But that can be done with the engine in the vehicle. It is kinda cramped, but I did it on my z71 so I know it can be done.

Transmission:
Upgrade the 4L65E to 4L80E - no shifting issues but she's a little sluggish and I don't think will like more power.

Will require a tune anyway so that should be on the list. You will need the 4l80e flexplate and either rewire the harness or by the conversion harness. Then an adapter for the tcase if your rig is awd or 4x4.. also driveshafts.

Rear diff?

Not sure what gears you have, but 4.10s are nice if you don't run 80 mph much remember if you have awd/4wd you need a set for the front too.

Not sure what all is needed here that makes sense....who is the best in this realm? I had reached out to Monster Transmissions but haven't connected yet.

Not gonna lie, if you can find a donor truck for most of the parts or junk 80e online.... use it as a core and get an Orielly reman if you have a store close. In person warranty stuff is soooooo much easier than dealing with an online person. And unless you are pumping stupid hp numbers a stock 80e will last behind a mild 6.0 forever. They came behind the 8.1 and I believe early duramax. I know the early 80e in my dad's old 6.5 with marine injectors and bigger turbo was fine. It didn't make a million hp but it was always overloaded by about twice the gvw lol.

Interior:
replace changer
slow project to turn interior into a sleeper cabin - long term project.

Exterior:
Swap the 20" wheels with 17/18s - anyone know the stock 20" wheel weight? Haven't been able to figure this out, would like to know so i can make sure I'm maximizing rolling resistance reduction.
Tint front windows
Bull bar
Probably respray the whole truck either the stock silver or a matte gray. Not sure.

Thanks for reading - she's an older beast now but man I love this truck...


View attachment 431869

 

[swathdiver]

your Wheels are the optional 20 inch wheels for the 2005/2006 (at least) GMC Yukon Denali...sorry to read they are leaky
here is a pic of them on the cover of the 2006 brochure

https://m.media-amazon.com/images/I/610RgWjFJmL._AC_SL1000_.jpg

Bill

Ya learn something new everyday! This refers to me not knowing those wheels were used on your GMT800s, cool!

@X-Factor Your wheel code will either start with an "N" or a "P" usually.

 

[X-Factor]

Compression check is a good start. To sonic check the block it has to be disassembled so skip that

Tube or manifold? The stock truck manifold is about perfect for these trucks maybe the Trailblazer ss intake beats it some, but not worth the effort if you aren't going wild

If you go headers get long tubes, shorties don't give enough power back for the cost and work to do them

Will be required for long tubes anyway

Maybe new injectors but stock flow rate should support most of what you do.

A tune on a stock engine is worth some, but if you do headers you will want to get one. Contact Blackbear Performance they are a sponsor here

At this age, I would consider replacing the oil pump Oring on the pickup tube. But that can be done with the engine in the vehicle. It is kinda cramped, but I did it on my z71 so I know it can be done.

Will require a tune anyway so that should be on the list. You will need the 4l80e flexplate and either rewire the harness or by the conversion harness. Then an adapter for the tcase if your rig is awd or 4x4.. also driveshafts.

Not sure what gears you have, but 4.10s are nice if you don't run 80 mph much remember if you have awd/4wd you need a set for the front too.

Not gonna lie, if you can find a donor truck for most of the parts or junk 80e online.... use it as a core and get an Orielly reman if you have a store close. In person warranty stuff is soooooo much easier than dealing with an online person. And unless you are pumping stupid hp numbers a stock 80e will last behind a mild 6.0 forever. They came behind the 8.1 and I believe early duramax. I know the early 80e in my dad's old 6.5 with marine injectors and bigger turbo was fine. It didn't make a million hp but it was always overloaded by about twice the gvw lol.

Great input! Thanks so much!