GMT400 Suburban with LS swap?

[redhat]

I enjoy coming on here bouncing ideas off of others so don't mind my potential rambling. Long story short, the '21 F150 is gone -- I'll probably post a thread on it once everything is final but that is no longer a worry. Been thinking on this idea as of late for a new vehicle.

I want to be able to tow and like the thought of leafs in the rear versus coils springs. I do not tow every day, but I would say I tow about 15 times a year with the heaviest load potentially being 8k lbs. I also like the Suburban body for covered storage as I'm always doing some sort of side IT work and hauling servers, equipment, boxes etc -- stuff that the back of a Burban is great for. I have put trailers on my 2005 and can definitely tell there's coils back there.

Since 2500 LSx Suburbans in GMT800 are either (1) sacked out beyond belief, (2) unobtainum priced, or (3) non-existant I'm thinking a GMT400 1/2 Suburban. I really like this body style, not a huge fan of GMT900 truck looks. Additionally, I love LS and they definitley beat cap/rotor/old small block ignition systems.

Swap in about 80k L96 with a cam , 4L80e and 3.73 gears. Should be plenty of tow power and even more important to me reliability. I would marry the 400 harness with an LS harness to retain all factory gauges, AC, etc.

Questions
- What would be a good cam for a Gen IV L96?
- Maybe the stock cam is just fine?
- How does one figure out what torque converter?
- I see info about swapping input shaft on the NP241 for the 80e. Are these t-cases OK to handle the more power?

 

[ArrestMeRedZ]

For the answers to your questions, I believe Clinebarger is your man. If he doesn't see this post, PM him about it. I'm sure others can provide good info but make sure he provides an input.

 

[tasch72]

TL;DR You're wanting to 6.0 LSx swap an OBS suburban for towing up to 8,000 lbs.

A cam wouldn't hurt, but that opens the "Midas Well". Depending on what cam spec you want, you might as well upgrade the valve train, and if you have the valve train out, you might as well touch up the heads...

A call to Texas Speed or Tick Performance will get you sorted on the camshaft situation

 

[Rob_Roy]

Why not look for a 2500 GMT400? That way you get the 4L80E, larger rear axle, larger brakes, heavier springs, etc.

I have a 1997 C2500 Suburban with the 5.7, it towed a 25' Camper from NY to AZ and back 20 times. 170k on it now, engine and transmission has never been apart.

 

[SwampSurvivor]

The 350 is supposed to be the best engine ever made I'm sure it would handle whatever you want to do with it. The weak point on a 1/2 ton Suburban of that era will be the transmission.

If I ever bought a K2500 GMT400 suburban it would end up on 99-04 Superduty axles.

 

[Graham Piccinini]

I miss my GMT400... Days of cheap LS swaps are kinda over, junkyards are up to speed on LS popularity. With this in mind - a K2500 GMT400 with a Procharger on the ol' small block (to me) seems like a better option. With upgraded cooling though. JMHO, but could be wrong...

 

[skyactiv]

The 350 is supposed to be the best engine ever made I'm sure it would handle whatever you want to do with it. The weak point on a 1/2 ton Suburban of that era will be the transmission.

If I ever bought a K2500 GMT400 suburban it would end up on 99-04 Superduty axles.

The 350 wasnt the best engine or V8 ever made. It was out in millions of cars-vans-station wagons-trucks-boats which made them cheap and easy to find and build what was coined a “beer budget small block” in every Car Craft magazine it seemed.

 

[clinebarger]

I enjoy coming on here bouncing ideas off of others so don't mind my potential rambling. Long story short, the '21 F150 is gone -- I'll probably post a thread on it once everything is final but that is no longer a worry. Been thinking on this idea as of late for a new vehicle.

I want to be able to tow and like the thought of leafs in the rear versus coils springs. I do not tow every day, but I would say I tow about 15 times a year with the heaviest load potentially being 8k lbs. I also like the Suburban body for covered storage as I'm always doing some sort of side IT work and hauling servers, equipment, boxes etc -- stuff that the back of a Burban is great for. I have put trailers on my 2005 and can definitely tell there's coils back there.

Since 2500 LSx Suburbans in GMT800 are either (1) sacked out beyond belief, (2) unobtainum priced, or (3) non-existant I'm thinking a GMT400 1/2 Suburban. I really like this body style, not a huge fan of GMT900 truck looks. Additionally, I love LS and they definitley beat cap/rotor/old small block ignition systems.

Swap in about 80k L96 with a cam , 4L80e and 3.73 gears. Should be plenty of tow power and even more important to me reliability. I would marry the 400 harness with an LS harness to retain all factory gauges, AC, etc.

Questions
- What would be a good cam for a Gen IV L96?
- Maybe the stock cam is just fine?
- How does one figure out what torque converter?
- I see info about swapping input shaft on the NP241 for the 80e. Are these t-cases OK to handle the more power?

You can call Cam Motion & have a cam custom ground for the application, Delete the VVT, Use a 3-Bolt Cam gear, LS2 Timing Chain & LS2 Timing Damper, LS2/LS3 Timing Cover.
The Timing Chain Tensioner required for VVT fail too often for my liking.

A stock LS3 Cam is often overlooked, But works great in L96's doing truck duty & is very cheap....Use a 1-bolt LS3 Cam Gear with a LS2 Timing Damper & LS2/LS3 Timing Cover.
I highly recommend new Valve Springs, Stock LS3 springs will be fine for a LS3 Cam.

You'll need to keep the Converter Stall Speed under 1900 RPM or so to keep from building a ton of heat while towing, This will limit your camshaft choices.

Have you considered a 6L80E? With a Twin Disc-Billet Front Cover Torque Converter & a Good Tune....These are quite reliable if you stay in the 2010 & up year range.......You'll have MUCH better ratios than any 4 speed will give you.
Buy a 4wd 6L80E & a 32 spline input NP241C will bolt right on.

Using a 6L90E is also a possibility, But you're stuck with Magna Powertrain MP1225/MP1226 T-Cases, Not a bad thing as their stronger than a NP241C.

IIRC.....GM limited the NP241C to rigs under 9200# GVW, Borg Warner 4401/4470 were used in heavier GMT400 trucks.