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19trax95's 1986 CUCV M1028A1

15457 Views 342 Replies 24 Participants Last post by  19trax95
So I have been looking for a decent square body for some time now. Didn't really have my eyes on anything in particular, but the frame and body needed to be in as good of shape as I could find.

Last week I came across this beast on marketplace up in Massachusetts. It's a 1986 Chevy M1031. Which is the military CUCV service truck.

It is I'm great shape. Frame is rock solid, and the cab has very, very little rust. It is also mechanically sound. A couple little leaks, but that's to be expected.

It has the 6.2 diesel, th400 trans, np205 t case, king pin Dana 60 front axle with a limited slip, 14 BFF rear with locker, and 4.56 gears. The service body is all aluminum. It used to have a PTO driven generator and air compressor, but those have since been removed. The PTO is still on the t case though.

My plans are to keep it fairly original, but add a few creature comforts to suit me better.
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Come on now. Go all the way and slap both of those bad boys on there! 💪:cool::ROFLMAO:
Lol the N/A motors don't always enjoy one turbo, let alone two.

Compression ratio is a bit high for forced induction. The 6.2 motors are 22:1 and the turbo 6.5 motors are 16.5:1.

My plan is to waste gate the turbo to around a 6psi max boost. Should make a difference while staying on the safer side.
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Got pretty much my final parts list picked out. Might start ordering this weekend.

So as of now, my list is as follows,

Rebuild kit for the GM3 turbo
Turbo master kit for GM3
Diamond eye 2.5" crossover pipe
3" downpipe
Walbro FRB-5 fuel pump
Cat spin on filter head
Intake gasket kit
Exhaust manifold gasket kit + bolts
Fuel pump block off plate with oil drain fitting

I'll also need lines and fittings for the oil feed and drain lines, but that'll have to wait until it's installed so I can decide what exactly I want to use since it'll depend how I route it.

I will also need to fab up the crossover and downpipe as neither one will bolt on super easy without modifications. Crossover will need to be shortened and downpipe will need some work as well. I'll need to make an air filter setup and plumb in the CDR valve. The 2nd battery will need to be moved since I am wanting to retain the 24 volt system.
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Fuel pump is ordered. I'm hoping to have it for this weekend, but I'm not banking on it. If it does get here by the weekend I'm hoping to have time to get it installed and wired up.

I'll likely leave the mechanical pump in place until I do the rest of the install.
Haven't had much time to work on the truck unfortunately. Between work, and fires/bbqs, and keeping the Ole lady happy, the truck just been sitting lol.

I did get my fuel pump, and will be ordering some more parts today or tomorrow. I think once all my parts are here I should be able to get the bulk of the work done in a weekend. It really isn't that much work compared to what I normally do, just this project will require some trial and error stuff when it comes to oil lines, and mainly the exhaust. That'll be the longest part is fabrication of the exhaust.

I'm planning on ordering a 6.5TD crossover pipe and then a 6.5td downpipe. I have not yet decided if I want to run the exhaust on the outside or inside of the frame. Outside of the frame will likely be easier with less welding, but then again it's not technically the "right" way to do it. Probably doing 3" turbo back, to maybe a 4" tip or make the last few feet 4" depending how I run it so it deepens up the sound profile a bit.

No muffler or anything obviously since the turbo takes care of that.

Edit: since it was on my mind, just ordered most of the rest of my parts. Turbo rebuild kit, crossover, manifold gaskets, clamps, and turbo drain kit. All that's left is the downpipe, and intake gaskets. The gaskets I'll get from napa locally, and the downpipe I'll get potentially locally if a junk yard has one. If not I'll order one up. I'd rather get a used one since it'll be cut apart and welded different anyway.
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Neat, you sure move faster on projects than I do.

So say you get the turbo on and you were to turn the boost up and snap a crank or need a new block. What would be the plans then? just pull a used and not turbo it?
Well the gm3 turbo I'm using is really only good for maybe 8psi before it becomes ineffective. They are waste gated to 6psi, which is what I'll leave it at.

But if anything happens to the 6.2 I'll either drop an LS in it, or find a cummins to drop in it. Wouldn't be worth going back with another 6.2 or 6.5 as much as I enjoy them. Nice thing about the truck being a 1 ton, is it has the bigger frame in it, so it'll handle the heavier motor like a cummins better than the 10 and 20 series trucks.

A big block wouldn't be out of the question either, but I'd prefer the simplicity of an LS if I were to go gas.
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So I am more than pleased with the service from kb diesel. Ordered my parts yesterday, basically right after I posted on this thread, and they will be here today.

Granted they are in PA, but they shipped literally within hours of me ordering, and they had everything I was looking to get in stock
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Got my parts today.
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Nice man this project is moving fast 😎👍
I got the electric pump installed today. Mounted it on the frame under the cab. Need to clean up the wiring a bit, but it'll be changed when I start the tie o project anyway.

I also need to remove the mechanical pump still. But I was looking around under the truck and right behind where I put the pump by maybe a foot or so, I noticed the rear brake line rubbing on its clamp that secures it to the frame. I messed around with it and cracked it. So now I need to do a rear brake line.
Brake line will get done today or tomorrow. Broke down and bought a nice hydraulic brake line flaring tool. Also grabbed some fitting and nicop line from work to make a new line up.

Won't be a ton to take pics of but I'll grab some of the fuel pump at least.
Got the brake line done today. Was pretty straight forward. Went right from the factory union back to the rear soft line.

I opted to delete the load sense valve and go right to the soft line. Shouldn't have any issues in doing so, but if I do, all I need to do is make one more short line.

Here's a pic of the fuel pump. I still want to put the wiring in some loom, but I didn't have any at the time.
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Drove the truck and the brakes are WAY better now that the load sense valve isn't there anymore.

Also gave the truck a quick wash.
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Looks great!
Thanks. Missed driving the truck the short time it was down. It definitely runs smoother with the new fuel pump.

Still have to delete the mechanical pump and put my spin on filter on there, but it's making progress slowly but surely. Been busy with other stuff and spending time with the Ole lady. But on the plus side, she wants to help me with some of it to learn some mechanical stuff, so that'll be the ticket to have an extra set of hands lol.
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Lucky dog!
Haha yeah definitely can't complain lol.
Drove the truck to work today. Definitely has a tiny but more pickup now with the new fuel pump. Nothing at all drastic, but is slightly noticeable. And it just overall runs smoother.
Turbo project is kinda at a stand still. Haven't had time to work on it yet really. I did get the turbo torn down and I may try and put it back together tonight. I've been letting some of the parts soak in carbon cleaner since they were pretty nasty and caked up.

I am also highly debating taking this truck down to outer banks with me next month. I can't drive it all the way down there. Well technically I could, it'd just be a long trip at 55 tops the whole way lol.

If I can find a place to store a trailer, I'll tow it down there. If I can't, then I'll just have to wait until I do a OD trans swap.
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