2000 Heavy 3/4 Ton Student Project

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Feb 6, 2024
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East Texas
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To be completely open and transparent: I own the truck, but it is more because of administrative policies and concerns over the district deciding to crush it after we are done with it (rather than having the liability should something happen after students worked on it). The truck will eventually be sold or traded to facilitate a new student project.

We're starting work on our first big project. This is a resurrection. The L31 is reportedly locked up. Our first order of business is to verify we can't get it to turn. We're pulling the plugs and soaking the pistons.

Assuming we can't free it up, we have a couple of engine options: I have a 355 short block fresh from the machine shop, but it is an older 2 piece main seal block. How much trouble to get this into the truck? Worth the effort?

We have a Gen 4 5.3 block shortblock, but it needs a full rebuild. Even with a the machine shop cutting us a break, we don't have the budget to build it out, much less swap it in. We'll have to do some fundraising. I REALLY hate fundraising.

We buy a pull out or donor truck engine freshen up and swap. Again that will take some fund raising.

Now, we do have some assets. The local pick & pull will let us have whatever we want, but pickings are slim. Trucks get jumped on quick and I usually can't get there fast enough. We have a Holley HP ECU we can use with Gen 3 LS harness. We have a variety of random SBC, LS and LT parts and an army of teenagers (for better or worse).

I'm completely open to any suggestions.


Gotta have 4 doors..... Rawhide, TOTY 2023!
Sep 18, 2019
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Houston, Texas
Simplest thing would be to rebuild the 5.7 in the truck, if it's buildable. Next best option is to source one from a similar age truck and build it if needed. Too bad y'all aren't closer to Houston as there are many trucks in the yards down here, 400s and the NBS/800s with LS platform engines. Hardset thing to find is a 6.0, but I do have one of those and the truck it came in.(2006 GMC Yukon XL Denali for sale).


Gotta have 4 doors..... Rawhide, TOTY 2023!
Sep 18, 2019
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Houston, Texas
To be fair, we honesty haven't decided what direction we're going yet. We're still trying to figure out what we have on our hands.
Once y'all get it figured out (what the possibility is of rebuilding the existing engine) let us know what direction y'all are going. Many people are here to help...


I'm Awesome
Apr 23, 2022
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Build it with a “teenagers budget” only buy things from Amazon or trading…
Make an Amazon wish list, that way people can buy stuff for the students and the project.

I know first things first to get it running…

Do things like a stereo, it will help them with the basics of wiring. Have wood shop built a sub box for it…(I’m sure a local stereo shop or a members have head units, amps etc to donate)

Simple upgrades like headlights, new chrome grill and window tint, all very cheap and easy for a teenager to do.

Buy a cheap muffler from Amazon and teach them to weld.

Frame detail, give a couple of kids some PPE, wire brushes and some black paint.

Rip the interior out and do a deep detail, power wash the carpet and clean the seat, throw a seat cover on it. Something to show the kids that elbow grease and hard work can really make an old truck really nice and you don’t need a lot of money to do it.

I see a dent in the bed, not sure if you want to do bodywork but maybe you could knock the dent out and make it look a little better, teach the kids how to buff out the paint.

They are starting with a nice truck to began with, hopefully you do a build thread to keep us updated. I would love to be a shop teacher with a project like that.
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Supporting Member
Supporting Member
Dec 20, 2023
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It is all conjecture until you find out if the existing engine is locked up and why it is locked up. If it is, then pull and disassemble and see why. All of these steps to this point are a learning process, as you are well aware of. A running engine swap should be the least expensive correction unless the existing engine is buildable. But nowadays so many bad engine fixes are "bolt in another one". The rebuilding process is done, more and more, by companies like Jasper and others. I am looking forward to what is found when trying to see what is good or bad about the existing engine.

Road Trip

Supporting Member
Supporting Member
Jul 8, 2023
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Syracuse, NY
These are my initial reactions off the top of my head:

1) Assess how your unique situation alters what project strengths &
weaknesses you have to work with. On the one hand, money is tight.
On the other hand, you have a large pool of 'affordable' labor. So all
things being equal, a more labor-intensive approach should get the nod
as opposed to trying to buy/fundraise your way out of a problem.

2) From your description, the goal of this truck is a stepping-stone to help
fund the next training vehicle. From my perspective as a hypothetical buyer,
a refreshed *stock* truck is more valuable to me than a modified truck, even
if the modifications are supposedly using a 'newer/better' LS engine and
associated ECU. (VCM)

Why? An unmodified truck = I'm relying upon what the factory design/mfg
engineers came up with. On the other hand, on a modified truck I'm now
relying upon an additional layer of 'engineering' by whoever did the work?

EDIT: With a stock truck I can use the FSM (Factory Shop Manual) to
evaluate/troubleshoot/fix the vehicle in the least number of steps & aggravation.

With a 'custom' vehicle I have to rely upon the custom documentation
on the mods. (usually zero) Or, I start perusing the internet for other vehicles
with the same mods? Thanks, but no thanks? :0)

Speaking of which, a strength of this forum is the cache of FSMs that we
use to keep these old machines on the road. If you don't already have
this data downloaded, set yourself up for success: (GM Service Manuals)

Were they working at a level where they first fully evaluated what the original
engineers did within their budget, and then reasoned their way through
to a successful upgrade? Or just they just throw a hodgepodge of parts at

Don't get me wrong, for I'm not casting aspersions at anyone in this conversation.
Instead, I'm just being candid about how I view *any* vehicle when I'm
evaluating it for purchase.


Given the above, if the engine really is seized, then pull it and perform a careful
mechanical post-mortem on what you uncover. What a great learning opportunity!

* Lots and lots of photos. Both 'undisturbed Big Picture' whole engine bay shots for future
hints during reassembly, as well as detail photos of the more intricate stuff like how the
distributor was clocked in the 'as found' condition.

Organize those photos into a searchable database for future student reference.
(Or just post them sequentially 'into the cloud' here into your 'rebuild thread'. :0)

* Teach them how to tear down & rebuild that truck without losing a single washer,
fastener, or small part that's seemingly insignificant, but is no longer in production,
is now made of unobtanium, and the replacement cost is measured in number of
hours scouring the Treasure Yards and/or the internet to recover from the lost part.

(Suggestion: Sandwich, Quart, & Gallon bags, Sharpie marker what it is + quantity
of items on the outside, followed by clear tape over the Sharpie writing. Lasts as
long as the aerospace 'bag & tag' method, with the advantage of being able to see
what's inside. (See attached.)

Bonus points for giving each bag a sequential, unique ID number,
so that IF a bag comes up missing you will know it. (And the sequential thing is
helpful, for the air cleaner wingnut should be in Bag #1, whereas the rear main
seal mount & associated hardware should be found in roughly the 100+ bag
neighborhood.) And ALL these bags must reside in a dedicated shelving setup.
How about Bag #1 all the way on the left, and bag #256 is all the way on the right?

I know that this may sound like overkill, but the strength of having so much semi-skilled
labor is also your weakness. Somebody in the 2nd period class gets interrupted, the
small bits get put down in some illogical spot, and by the 5th period those parts are
well on their way to being lost forever, despite well-intentioned efforts to the contrary.


I could go on & on, but let's stop here and summarize. If the engine is seized, pull it,
make careful observations at *each* step. Do things that a commercial shop can't do
because of time constraints. For example, there are 17 bolts attaching each cylinder head.

IF you take the time to measure the amount of torque it takes to *remove* each one, you may
uncover a valuable clue as to why the head gasket failure occurred. (Remember, this truck
came off the assembly line 24 years ago, and since them a too-fast/substandard head
gasket replacement could have been performed.)

And keep taking that engine apart until you can finally turn the crank again. Maybe you
will find a spun rod bearing. And if it's the #1 and/or #2 rod bearing, you can then
teach them that a loss of engine oil pressure always affects the furthest away rod
bearing first. (Tip of the hat to L31MaxExpress.)

And so on and so forth. Bring it back to solid, original, working condition, have the
photos that can *prove* your claims of goodness, and IMHO you will get a lot more
for that truck than making it mo' betta with more modern bits.

Apologies for the length, but I really like the opportunity you are putting together that
can/will favorably impact a group of future mechanics / mechanical engineers / anyone
who will need the tools to see a complex project through to completion for the least amount
of setbacks / frustration / blown deadlines / cost overruns.

If you ask me, *every* high school should feature a project like this. (And classes on personal
finance as well, but I won't go there at this time. :)

Good stuff. Kudos on you for making this happen.

Cheers --


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