1990 Suburban LQ4/4L80E/D60/14Bolt swap

[KeithT712]

New to the forum and first time build thread but something I've wanted to do for some time now. Find myself constantly searching for answers so figured maybe somehow it may help a few people along the way. Or may even help get some tips and pointers from everyone on here.

The idea was simple, swap a 6.0 Lq4 out of a 2500HD along with the 4l80e into a square body suburban for a nice old burb that could pull a trailer or travel long distances no problem.

While I'm just starting this now this project actually somewhat started about 6 months-year ago, so I might breeze through the past view months to catch up to where I am now. (as long as I can figure out uploading pictures)

And again any input/advice or pointers is appreciated, still have a long road ahead
I'll continue to update this as progress continues as well any part of the build can be seen on instagram under #lsxburb

-Keith

[KeithT712]

This all started where most of my projects seem to start... A good deal on craigslist

I found a 90 square body suburban that was listed for a couple months that seemed fairly clean and worth looking at, at the same time I had found a not so clean (dented and abused) lifted suburban mud truck with dana 60/14b axles and 39.5 tires which peaked my interest. I found myself traveling to both ends of Vermont to look at each and bring back home with me

[KeithT712]

The weeks/months that followed were mostly spend working on the mud burb, with a 4 speed (sm465) swap and tune up to get it ready to play in the mud. But that is another story about another truck for another time

About mid summer 2017 I decided that black suburban frame wouldn't be a bad start to project being that it was very clean ( no real rust issues) and the body would either be removed and put back on or transplated to the mud truck. So the tear down began and the body was removed.

Next the frame was stripped down and I attempted to sand blast the surface rust that was there using a portable sandblaster... that didn't last very long granted I the sand blaster I had probably wasn't the best and spend more time refilling than I did spraying so a phone call was made to a local powder coat shop here in vermont to sand blast and coat it for less hassle and in the long run less money

[KeithT712]

When it became time to get new parts Off Road Design was the one stop shop for most of what I needed: (which has become a bigger and bigger list)
HD Engine Crossmember
HD Motor Mounts
LS Converversion plates
HD Front and rear shackles
Steering box brace kit
4" Tuff Country EZ-ride lift springs and shocks
U bolts and top plates for the dana 60/14 bolt

All of that had me covered for quite some time. Ofcourse after seeing how the frame came out at powder coat I decided to do the same with the 1 ton axles I had picked up so both were stripped and cleaned and sent off along with other misc parts

[KeithT712]

Along the way I checked craigslist and similar sites religiously in hopes of finding a complete donor truck, I could have just found and pulled a junk yard motor but I wanted a complete truck to take my time and work with. Eventually I found a lowish mileage (~150k)2002 Chevy 2500hd 6.0 auto posted online. the body was rough and the idle was off (intake gaskets) but the truck had been a fleet maintained vehicle for a plumbing outfit its whole life. Another trip across vermont in a flat bed and it was at its new home.

Eventually when the time was right the motor transmission and transfer case were pulled out, valve covers were pulled and the inside of the motor appeared clean but was still stripped down and block send out to be checked and hot tanked along with new bearings and cylinder hone and crank polish.
Ended up selling the transfer case out of the truck for $500
seeing how driver side drop transfer case wasn't going to work with my gm 60, and I'd prefer not running a ford axle on this one

[KeithT712]

Can't seem to figure out why the pictures keep posting upside down and sideways but still we'll push on

Deciding on what transfer case to put behind the 4l80e was easy thanks to Off Road Design and their 4l80e/np205 adapter getting the best of both worlds I went with a 205 built specifically to be bolted right up (with a speed sensor that would plug right in to the ls harness also) as well as a twin stick shifter set up (mostly because I've always wanted to run one of them)

I'm sure there are other options that can be done, just 205 is what is run in the mud burb so I see no reason why a tow rig cant have one too. The first hurdle with this setup was needing the tranny crossmember and mounts out of and earlier truck (pre 85 i believe) that would have come with the 205, which was easily found either from local yards or in this case eBay for a clean one

Next was to re assemble the front and rear axles and place them under the springs

[83GMCK2500]

Awesome! I followed the link in your sig from the bumper trim thread and now I'm stoked to follow this build. I've never been as far east as you are and from what I've heard I'm amazed there was still frame under the '90.

[KeithT712]

Originally Posted by 83GMCK2500

Awesome! I followed the link in your sig from the bumper trim thread and now I'm stoked to follow this build. I've never been as far east as you are and from what I've heard I'm amazed there was still frame under the '90.

Honestly I was just as surprised haha, the frame in both the 90 and in the mud truck were practically spotless, the 90 had a little surface rust but nothing that sand blasting and powder coat couldn't take care of

[83GMCK2500]

I was just looking closer, the '90 1500 is this build correct? Where did the D60 and 14FF come from? Was the 14FF with factory disc + parking that came in your 2002 donor/parts truck not rebuildable? Moving spring perches doesn't appear to be out of your skill set.

[KeithT712]

Originally Posted by 83GMCK2500

I was just looking closer, the '90 1500 is this build correct? Where did the D60 and 14FF come from? Was the 14FF with factory disc + parking that came in your 2002 donor/parts truck not rebuildable? Moving spring perches doesn't appear to be out of your skill set.

Thats a good question and it was a cross road that I was at for a decent amount of time The 90 is in fact a 1500, the axles where bought with a matching set of 44 inch bloggers for my mud truck. They're 4.56 gears with rear locker, although the 02 was 4.11 with limited slip g80 diff, which led me to a 4.11 vs 4.56 gearing debate with almost everyone i know. Basically I would either have to re gear the front or the rear

I decided to run with the 4.56s to start mostly because they were already in the older axles and I'm curious to see how they do with 35s.

The 02 axle is a little rougher on the outside than the 4.56 axle was but again nothing that couldn't be cleaned up with some sand (although i never got as far as disassembling it), I figured the option is always there anyway once i decide which gear ratio is going to stay with the truck

[KeithT712]

Slow progress this weekend also, the northeast had a gorgeous weekend so I found myself enjoying it at Killington mountain for the most part but did manage to squeeze in some build time...

Last few finishing touches on the rear end, installed my rear brakes (85 k20 front brakes), tuff country shocks on, and finally hubs and axles in. Now were about ready for wheels and tires

[83GMCK2500]

Originally Posted by KeithT712

Thats a good question and it was a cross road that I was at for a decent amount of time The 90 is in fact a 1500, the axles where bought with a matching set of 44 inch bloggers for my mud truck. They're 4.56 gears with rear locker, although the 02 was 4.11 with limited slip g80 diff, which led me to a 4.11 vs 4.56 gearing debate with almost everyone i know. Basically I would either have to re gear the front or the rear

I decided to run with the 4.56s to start mostly because they were already in the older axles and I'm curious to see how they do with 35s.

The 02 axle is a little rougher on the outside than the 4.56 axle was but again nothing that couldn't be cleaned up with some sand (although i never got as far as disassembling it), I figured the option is always there anyway once i decide which gear ratio is going to stay with the truck

A good friend of mine had a 3.73 geared truck that received a CUCV rear (+ regeared front) when he started towing with it for a while and he said the 4.56s +35s were almost the identical to the 3.73s and stock tires.

Might be too bad you already bought brake parts for the rear axle, I'm not sure if you've seen the 4th product down here: http://www.fourwheeler.com/product-r...-new-products/ I came across it on Pirate a while ago and bookmarked it.

Did you mention, what all will you be doing to the 6.0L?

[KeithT712]

Thats honestly the outcome I'm hoping for with the 4.56s, I think i'll be happy with them just didn't want to spend the money on a locker for the front axle until I know for sure

I wish I had seen that sooner although i cant find brackets or prices on their site, the brake parts wouldn't be a complete loss on my end if i do something different I can just as easily transplant these brakes onto the 14 bolt under my mud truck

And I hadn't mentioned much of the 6.0 yet but its perfect that you asked because that is my next step. After I pulled the motor out of my donor it was completely stripped and sent out to a local machine shop for hot tank, new cam bearings, cylinder hone and just a general check over, along with my crank which was hot tanked and polished.

Once the motor was back to me it was taped and painted, all new bearings, rings & gasket sets ordered and basically its just been covered up on my engine stand waiting for me to reassemble it. (just wanted to finish the axles first)

For a cam I ended up going with tick performance tow max stage 2 after talking with them, I wanted something above stock but nothing too crazy as I hope to tow with it and travel some.

For Heads I'm leaning towards a set of 243/799 for the bump in compression but still haven't made my mind up there either, I figured once the bottom end is reassembled ill have no choice but to pull the trigger one way or the other. But at any rate hopefully I will begin putting the motor back together this week/weekend

[NorCalAnthony]

Very cool build you have going here dude. You're doing a lot of similar stuff that I plan on doing to my K5 project so I'll be following along for ideas.

So did you just do a quick hone to freshen up the hatching on your cylinders or did they do more of a .005/.010 cleanup hone? If you wind up going to an oversize piston you can go with flat tops to pick up around the same 10:1 compression as swapping on 243/799 heads with the dished pistons.

[KeithT712]

Originally Posted by NorCalAnthony

Very cool build you have going here dude. You're doing a lot of similar stuff that I plan on doing to my K5 project so I'll be following along for ideas.

So did you just do a quick hone to freshen up the hatching on your cylinders or did they do more of a .005/.010 cleanup hone? If you wind up going to an oversize piston you can go with flat tops to pick up around the same 10:1 compression as swapping on 243/799 heads with the dished pistons.

Appreciate it man! Look forward to seeing some pics of yours as well, I'm sure the ideas will flow from both of our projects.

Basically the block was just freshened up and left the bore size, I had thought about swapping to flat top pistons for a bit but never pursued it although I do keep an eye out locally for a good deal on an Lq9 if there ever is one.

Honestly I haven't touched the inside of a motor in a few years so its also going to be a bit of a re learning curve and figured i'd just keep it simple for now (not that swapping pistons would be a giant task)

[NorCalAnthony]

Originally Posted by KeithT712

Appreciate it man! Look forward to seeing some pics of yours as well, I'm sure the ideas will flow from both of our projects.

Basically the block was just freshened up and left the bore size, I had thought about swapping to flat top pistons for a bit but never pursued it although I do keep an eye out locally for a good deal on an Lq9 if there ever is one.

Honestly I haven't touched the inside of a motor in a few years so its also going to be a bit of a re learning curve and figured i'd just keep it simple for now (not that swapping pistons would be a giant task)

I hear ya, I haven't been inside an engine since high school and trying to tinker with these newer motors can be intimidating. I'll be using an LS2 w/4l80e that I was able to pick up cheapish for my swap. The only downside is the LS2 has a spun rod bearing and the crank is toast so I'm having to save up for a stroker kit now... Probably be a while before I start a thread with me being stuck in the parts gathering phase, I don't think anyone wants to read about that lol.

So with your new 4 wheel disc setup, were you going to do anything different with the master cylinder and proportioning valve? Seems like some people run their existing stuff with no issues and other people have to swap out the MC and prop valve to get everything to work right.

[KeithT712]

Sounds like an awesome project NorCalAnthony! I've always wanted to do a stroker... maybe on my next one

As far as master cylinder and proportioning valve i'm thinking about going with something like the wildwood master cylinder with adjustable proportion valve but still haven't completely decided there yet either, figured ill sort it out once the body is on

[KeithT712]

Managed to make a little progress within the last week, re assembled the lower end last weekend with my new rings and bearings, put on the cloyes timing set and lingenfelter oil pump and then all new gaskets for the oil pan and front and rear covers.

Took a solid day of cleaning and measuring to get all the pistons in but overall pretty smooth and easy.

Finally with the help from a few buddies got the motor and transmission set into place and mated together with the tci flex plate and torque converter

And ofcourse daisy the shop dog had to inspect all the work to make sure it was done right

[KeithT712]

Not much news this week, holidays have kept me pretty busy although I did finally manage to track down a Warn Enforcer winch bumper for the burban! Its in decent shape but thinking my best bet will be to sandblast and powder coat the brackets and have the chrome redone. Basically just adding more to the project but it'll be worth it in the end!

Side note and unrelated but also picked up an 87 V30 Crew cab dually, 454 th400 np205! throwing it on the back burner for now but considering a 12v cummins with a nv4500 swap in the future but we'll see. Thats all for now if anyones reading wish you all a merry Christmas and we'll see if Santa brings the LSX burb anything new this year!