I added a 99 2 door Z71 Tahoe Sport with a rod knock to my hooptie fleet several months ago. Body and interior are pretty clean for the miles. Initial plan was to do a quick swap with a low mile 350, but that ended up selling before I could make the trip to grab it. Searching for a low mile or rebuilt 350 pushed me to an LS swap. The swap is moving slower than I'd like, so I thought a build thread would help keep me motivated.

I bought an 80k mile L59 (flex fuel) 5.3 out of an 04 Tahoe and also picked up the front spindles, brakes, and CVs to swap the larger NBS calipers over to my OBS. My original plan was for this to be a simple project. Clean the engine off, stab it in, and go, but scope creep ended up taking over. I decided to do a hydroboost conversion to take advantage of the PS pump already on the engine, stay with DBC instead of DBW (L59 purchased is DBW), and to do a cam swap.

The only "go fast" parts I've picked up are a BTR stage 2 "no spring" truck cam and Dorman Fast clone truck intake. I've also snagged most of the other swap parts required to drop into an OBS. I'd like to run E85 at some point but didn't get the flex fuel sensor with the engine. I also had to pick up a different ECM that supported DBC. Still doing some research on what's needed to get it running in the OBS.

I'm hoping to get the engine in the truck by the end of January (still working on cleaning, painting, and swapping gaskets) with the wiring harness converted over and first start up by end of February. I'm planning on using most of my OBS wiring harness and repinning it to work with the newer ECM.

The day I brought her home:








Ready to be torn down:


Dorman truck intake looks quite a bit better than the factory NBS intake. It's going to get ported to remove the wedges in the intake runners, and I may shave the engine cover mounting brackets/standoffs.



Strange casting wedges:


I expected to find some sludge, but it's pretty clean under the VCs.

He considered LS

In!

Looks like a fun project!

I love 2 door Tahoes

kudos to you for following the board rule to every project (LS swap it)

In.

ETA. Do you IG? C-10 buddy of mine just finished sama swap. Lots of pics.
https://instagr.am/p/Bkx_StjAgby

Love the 2 doors and that one looks pretty clean. Wish I never sold my 98.

His looks 100x cleaner than mine will likely be. I'm just hoping I get it done soonish. I tend to get bored with projects when they're about 80% finished. My Bronco has been sitting for nearly a year with just a handful of things to finish.

I want the Tahoe to be the yin to the Bronco's yang - a comfortable 4x4 "cruiser" that looks mostly stock with some decent power. One reason I bought this one is it was fairly unmolested. No weird aftermarket 22" rims, no lift, no electrical hackery, just a plain stock truck.

Got the new cam installed today. Had to improvise on tools to hold up the lifters. I tried dowels, crossbow bolts, and finally found a piece of all thread and metal rod that fit.





Also pressure washed the block. The heads cleaned up nicely. I'd thrown a quick coat of Chevy Orange to the VCs to see if I liked it. Pretty sure I'm going with the orange VCs and painting the block black. The timing cover also needs a coat of paint. I hit the block with some Ospho. It'll get to sit until it warms up enough to paint



Timing cover has to come off again to install a new cam retainer. Also replacing the timing cover gasket, front main, oil pan and VC gaskets. I've debated replacing the oil pump and timing chain, but I think I'm going to let it run with what's there for now.

That's awesome. What about gauges? Are you able to use your stock gauges or are you going w an aftermarket set?

Timing chain is fine, but I definitely recommend replacing the pump and oil tube pickup o-ring. Oil pump went out on Basic Birch's OE 4.8 and I'm rather certain AgWrangler had to replace his oil pump immediately after getting his swap in & running.

The Melling M295 is what you want, it's $60 off Amazon. Order a Felpro ring, I believe it's the red one if I recall correctly.

Centerpole90 said:

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That's awesome. What about gauges? Are you able to use your stock gauges or are you going w an aftermarket set?

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Gauges integrate directly with the OBS so I'll be running stock. I intend to use most of the Tahoe's existing harness which can be repinned to work with the LS computer. (Thanks Chevy for using the same parts and connectors forever) I believe the only new wires I have to run are for the coils.

silverado_lover said:

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Timing chain is fine, but I definitely recommend replacing the pump and oil tube pickup o-ring. Oil pump went out on Basic Birch's OE 4.8 and I'm rather certain AgWrangler had to replace his oil pump immediately after getting his swap in & running.

The Melling M295 is what you want, it's $60 off Amazon. Order a Felpro ring, I believe it's the red one if I recall correctly.

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.......I was afraid of that. I already had that Melling on my parts list but had decided to take a chance with it. Guess it isn't worth it to save $60-70. I already have a new pickup o-ring. Planned on replacing it when I do the pan gasket.

Thoughts on replacing the knock sensors/harness? It's ~$80 for the set and easy to do on the stand vs having to pull the intake after the engine is in the truck, but I don't want to spend the $$$ if I don't have to.

I'd pull the existing harness and give them a visual inspection. I often break the old connectors on the harness, suggest having a replacement ready.

Of course, Ac Delco only for sensors & harness. Summit has a good price on the cam retaining plate if you haven't already ordered it.

silverado_lover said:

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Timing chain is fine, but I definitely recommend replacing the pump and oil tube pickup o-ring. Oil pump went out on Basic Birch's OE 4.8 and I'm rather certain AgWrangler had to replace his oil pump immediately after getting his swap in & running.

The Melling M295 is what you want, it's $60 off Amazon. Order a Felpro ring, I believe it's the red one if I recall correctly.

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Facts.
Definitely would recommend replacing the oil pump. I second the Melling.

silverado_lover said:

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I'd pull the existing harness and give them a visual inspection. I often break the old connectors on the harness, suggest having a replacement ready.

Of course, Ac Delco only for sensors & harness. Summit has a good price on the cam retaining plate if you haven't already ordered it.

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Looks like new knock sensors are in order. The front one looked like it had been recently replaced. When I pulled the harness from #2, I found this.



Tried banging on several different sockets that kept rounding. I finally broke it off so I could get the valley cover off. Not sure what my plan is to get the broken stud out. Really don't want to drill it. I need to get some more gas for my torch. Hopefully heat and vice grips will get it to turn

I have a stud just like that in one of my blocks...torch and vise grips didn't work.

I think easiest would be welding a nut to top of stud...I haven't gotten around to this myself yet.


But hey, at least you're not doing this with the engine installed!

I might try that tomorrow after I do the oil pump. I have a manifold bolt broken off in one of the heads too but have been too lazy to get the welder out. Probably need to do it before I paint.

It would certainly suck trying to do this in the truck. Terrible design by GM. I'm going to RTV in the new wiring harness so water can't get in. At least this gave me a reason to stick the valley cover in the parts washer.

Welding didn't work but a step drill and some vice grips got it to spin out. What a mess... Would have really sucked to do with the engine in the truck.

My original intent with the build was to just swap in a stock motor with a $50 VATs delete and run a stock tune. Now that I've added a cam, I'm thinking about tuning. Silvy or others - how hard is it to learn enough of HP Tuners to dial in a somewhat decent tune? I have a wideband I can use for tuning. I know I can go with Black Bear or one of the local Texas tuners, but cheap ebay turbo kits have started calling my name and may end up on the truck in the fall. I'd really like to be able to make changes myself without having to trailer it to a tuner in Austin or elsewhere. I never had good luck doing remote tuning on my Lightning and would really prefer to take the truck to someone in person if I go that route.

I haven't had much time this week to work on the motor, but I did pick up several interior parts for the build...

120mph Escalade cluster. My stock cluster has a bad stepper motor on the gas gauge, and I think the extra 1k on the tach will be helpful with the LS



99 Escalade console with the Bose sub. Console will be painted SEM gray. I'll likely recover the lid with vinyl and add a filler panel with inverter where the rear radio controls go. I hear the Bose sub isn't terrible so I intend to hook it up. I'm past my boom boom phase of stereos and just need some low end fill. Usable cup holders are going to be awesome.




Also bought a steering wheel from a Saturn Vue. These are essentially the same wheel as the 06 Corvette. I'm hoping to find an upper steering shaft I can swap over. I know other cars that use the same style wheel have a removable upper shaft, but none of the GM parts diagrams show one for the Vue. May have to hit the pick and pull to check a few out. I hope the splines are cut the same as some other GM shaft if the Vue's isn't removable.

Having radio controls on the steering wheel is a must have for me these days. I'm looking for a blank left side cover like the Vettes have since the OBS has its cruse on the multifunction switch. I don't believe the cruise buttons can be used with something like a SWI-RC. Need to see if Alldata has the resistance values for the cruise side.

Escalade cluster is the way to go.

Being just a mild cam only 5.3, shouldn't be too hard to get it running decent w/ HP Tuners. Figure it'll be hard to hurt it much either, a good vehicle to learn on

Slowly getting things together. The engine is resealed and mostly back together.

I plan to start depinning the Tahoe's stock harness today. Hope to have the harness work done in 2 weeks so I can pull the engine the weekend of the 2nd.

In a moment of weakness, I bought a 2500 stall converter. The price was right, and I didn't want something higher since i do intend to do some slower off road driving with the truck.

It's so close I can taste it. Had the ECM tuned last week with a starter tune Once the engine is running and exhaust built, I'll run over to clean it up on the dyno.

I've repinned my existing ECM's harness into the LS connectors and made up harnesses for the wires I need to add. Would really love to get a first fire next weekend. I really need to do some clean-up on my stock harness.

Out with the old:


In with the new:

Any thoughts about the dash? On something that new is that the kind of thing where uncracked ones are available or is there some other option?

The Fife said:

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Any thoughts about the dash? On something that new is that the kind of thing where uncracked ones are available or is there some other option?

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i'm hoping to snag an uncracked one when I'm in DFW this week for work. I have a lead on one. I pulled a dash at the JY for my Bronco, but really don't want to deal with the time/misery involved again. I hear they're easier to pull on the Tahoes

Progress is being made. Wiring is all connected except for the TPS, IAC, and MAF. Waiting on my soft jaws for my vise to make up the AN lines for the fuel system.

It was late last night, and I was impatient so I cranked her over. She cranked and pumped gas onto the floor (oops) but at least I know some stuff is hooked up correctly. I'm happy the ECM is communicating with the ignition, fuel pump, and starter, and the flex plate adapter went on correctly.

I'm hoping she runs by the end of the weekend. After she runs, the intake will need to be pulled to clean up the rats nest of wiring I have. I left the injector and other harnesses long to make sure I had plenty of room. I also want to chop out some stuff from the OBS harness (EGR, steering sensor, left over ignition stuff) to clean the loom up.

I am a bit concerned the 4l60 is held in by only 5 bolts now. The LS removed one of the bell housing bolt holes and added several into the oil pan that don't line up with my bell housing. I replaced the studs with grade 8 bolts to make things easier to remove in the future. Silvy or others - any concerns with this? Also, does anyone have inspection plates for a 4l60 and an LS? My engine didn't come with the plastic covers and my old metal plate doesn't fit now.

On a related note....a buddy has a nice lifted 2d 98 Tahoe w/ a pretty new crate engine and he's thinking about selling it. Only problem is that it's 2wd.

How hard would it be to covert to 4wd? Transfer case & front diff plus linkage etc?

Damn son, you're overachieving with 5 bell housing bolts. I've never ran a TC cover since the swapdoodle and not sure if one is made

drumboy said:

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On a related note....a buddy has a nice lifted 2d 98 Tahoe w/ a pretty new crate engine and he's thinking about selling it. Only problem is that it's 2wd.

How hard would it be to covert to 4wd? Transfer case & front diff plus linkage etc?

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I'd probably swap in a solid axle instead of an IFS differential. On top of what you already named, new drive shaft, new tailhousing for transmission, cut a hole for transfer case shifter, possible transmission reprogramming, etc.

drumboy said:

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On a related note....a buddy has a nice lifted 2d 98 Tahoe w/ a pretty new crate engine and he's thinking about selling it. Only problem is that it's 2wd.

How hard would it be to covert to 4wd? Transfer case & front diff plus linkage etc?

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Buy it, slam it, sell it for a profit then buy a nice 4wd. The 2wds are much less common than the 4wds and people love to slam them.

silverado_lover said:

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Damn son, you're overachieving with 5 bell housing bolts. I've never ran a TC cover since the swapdoodle and not sure if one is made

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Just didn't feel right not having more bolts in there. The trans is leaking somewhere. Was wet when I pulled the cross member to get the upper bell housing bolts. I can't tell if it's coming from the trans or transfer case. Someone has been in the trans fairly recently. The torque converter had a 2016 rebuild sticker on it.

I tend to stay away from working on auto transmissions so it may have to go to a shop to figure the leak out.

I did pick up a clone of Tech2win that should help diagnosing any random crap the swap causes. We'll see how much it freaks out trying to read the OBS once I get things running. I don't think it should be much of an issue since the Express Vans kept the 5.7 for several years and ran a 411 computer.

It's alive...mostly.

Need to plumb in the flex fuel sensor and clean up lots of wiring. I was determine to get it running before pulling the intake to loom all the added wires. Now I need to figure out the right length for some I made too long, pull the loom off the factory harness to see if I can route some of the original connectors better, and extend some other pig tails. Lots to do, but at least it goes vroom vroom.

Congrats!

Damn, it sounds great.