CREW CAB LONG BED K3500 NV4500

[94K3500PROJECT]

So I searched for ages it felt like for a crew cab GMT400 with an NV4500. Originally was looking for a 454 Vortec truck with a 5sp but those never popped up.
I was OK with doing some engine work and wanted OK unloaded Highway MPG so ultimately maybe the BBC wasn’t for me.
I ended up with a 94 K3500 dually with a service bed. Not what I was looking for but it’ll do.
Aside from a leaking gas tank and AC that didn’t work it drove fine, ran great and had a little over 109k miles.

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I thought hell once the service bed is removed and I replace 3 of the doors it’ll be “rust free”.
For a NE Indiana truck that was just a driver that would have been true enough.

Part of the reason for this purchase was to do a BUILD. A build that was a replacement for the purchase of a NEW truck.

I dug into this one cleaning things up and buying parts etc. After HOURS of cleanin the frame and removing rusty crossmembers and shock brackets etc I was second guessing my choice in teuck

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Somewhere along the line I bought a parts truck that DID have truly rust free parts.
It came with a Texas title and from what I understand has been passed around a few times to other GMT400 guys.
It was super beat and dirty but rust free and came with a new 6” lift kit and a few random parts

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Fast forward even further and long story shortened slightly is that the parts truck is the new base for the build. ‍

 

[94K3500PROJECT]

So I have some long term performance goals for this truck that I’ll spell out here because I want to have this documented to help keep those performance goals in mind.
1: 500lb/ft at the rear wheels at 3500rpm. I’ll be doing this with a old school SBC and will take a few years to achieve.
2: Ride AND drive quality much better than stock. Ride quality better than stock K3500 and nearly as good as a K1500 with a mild torsion bar crank. Driveability better than even a stock K1500 (on a lifted K3500)
3: quiet and comfortable. This is a large encompassing goal that includes sound deadening, heat insulation, new weatherstripping, updated options and conveniences etc, etc.
4: great brakes. Between a lift, 35” tires and 22” wheels, and towing I want and need the brakes to be really good.
5: Reliability. This kind of goes hand in hand with the GMT400 as long as I don’t stray too far from the platform in the build process
5: 13mpg on the Highway at a minimum 15 maximum. No small feat for a gas powered truck that’s lifted on 35’s



Somewhere along the line I really started moving away a little from the OEM plus look and build to something that was a hair more than that. I don’t want to lose the functionality of a rebuilt HD truck but do want it lifted, on nice 22” wheels and most everything to look nice. (More on all this later)

 

[94K3500PROJECT]

So I removed all the crossmembers and brackets from the parts truck thinking I’d use them on the original truck
After cleaning them up and giving them a quick painting I decided this wasn’t good enough

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[94K3500PROJECT]

Found a powder coating shop that does decent work for a decent price and had a few things done

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[94K3500PROJECT]

Outlining some plans toward the performance goals to stay on track and to build the recipe as I go outlining how I got there and why I’m doing what I’m doing.

1: Engine performance.
This will be a baby step approach.
- I’m starting with a TPI intake setup from a 3rd Gen F-body along with a Dynamic EFI ECU.
Hedman Elite headers, a custom 3” exhaust with H pipe and some sort of relatively mild but not restrictive muffler.
The TPI intake setup is the IDEAL truck intake and with heavy porting of the base and AS&M runners you can get a nice boost in power while keeping or even boosting low end torque.

The headman elite headers have a 3/8” flange and 14gauge tuning. The HD material in these make them the best choice. I don’t want any leaks in the future.

-The next step is some sort of an aluminum head. I do have a spare 5.7 Vortec and those heads were an option but feel like the aluminum route, even if a China special head offers some advantages I’d like to have.
During the head swap I’ll also be doing a cam swap.
This one will be very mild. I don’t want to shift the power band up any higher than stock. If the block is drilled/tapped for a roller setup I may run a stock LT1 cam/lifters
-Next step will be a 400ci dart Shp based short block. This will be a roller cam setup for sure with a little more duration than stock, more lift and less LSA.

At this point this should easily be a 400ft/lb at the rear wheels setup so 500 should be very easy with the next step....

-Finally an STS remote turbo setup.
Even in single turbo version these have the ability to put down big power, have a clean engine bay and enable you to still use those expensive headers.
This will actually make MORE than I’d like because of long term reliability. With an SHP based bottom end, low RPM’s (5K Max) and a boost controller an additional 100-150 lb/ft is a nice easy goal.

This will have enough torque down low to pull an enclosed race trailer or travel trailer in 5th with ease, and when under boost plenty of power for passing, pulling up steep grades and in traffic.

 

[Erik the Awful]

I don’t want to shift the power band up any higher than stock.

Then I'd clean up the ports on the Vortec heads and run them. Check them carefully for cracks. Call your favorite cam maker and they'll set you up with a cam that works great. I'd save an aluminum head upgrade for the 400.

I gotta say I'm a little jealous of your 3500, but driving through the parking lot at work yesterday, and having to swerve around the few crew cab long bed trucks that guys insist on parking in our cramped lot, I'm glad for my shorty truck.

 

[94K3500PROJECT]

Then I'd clean up the ports on the Vortec heads and run them. Check them carefully for cracks. Call your favorite cam maker and they'll set you up with a cam that works great. I'd save an aluminum head upgrade for the 400.

I gotta say I'm a little jealous of your 3500, but driving through the parking lot at work yesterday, and having to swerve around the few crew cab long bed trucks that guys insist on parking in our cramped lot, I'm glad for my shorty truck.

The turning radius is definitely garbage too lol.
I’m looking at doing a GMT800 knuckle/brake upgrade and am curious if that will do anything for the turning radius or if it’s just what happens with a 75’ long truck LOL

 

[skylark]

35s on 22s, 6" of more wind drag, 500tq to the wheels and getting 13-15mpg (equivalent to a lot of diesels with similar lift/tires) out of a sbc is quite optimistic. I'll ride along for the results.

 

[94K3500PROJECT]

35s on 22s, 6" of more wind drag, 500tq to the wheels and getting 13-15mpg (equivalent to a lot of diesels with similar lift/tires) out of a sbc is quite optimistic. I'll ride along for the results.

No it is I agree.
The torque number will help though as eventually I’d like to adjust the gearing to run a lower RPM and still pull a decent amount of vacuum. Ultimately I’d like to install a Gear Vendors splitter. Splits between 2-3 and 3-4 would help when pulling a trailer, their OD is supposedly stronger than the OD in the NV4500 and unloaded at 70 and double over I could be turning just 1,700 rpm with 35’s and 4.56’s.
That’s a big chunk of money to save a couple MPG so I’d really like to track someone down with that combo that would give a ride along before spending that kind of $$$

The first thing I’ll play around with is the Lean Cruise Mode tuning in the Dynamic EFI system to see what kind of gains are possible there.

 

[skylark]

No it is I agree.
The torque number will help though as eventually I’d like to adjust the gearing to run a lower RPM and still pull a decent amount of vacuum. Ultimately I’d like to install a Gear Vendors splitter. Splits between 2-3 and 3-4 would help when pulling a trailer, their OD is supposedly stronger than the OD in the NV4500 and unloaded at 70 and double over I could be turning just 1,700 rpm with 35’s and 4.56’s.
That’s a big chunk of money to save a couple MPG so I’d really like to track someone down with that combo that would give a ride along before spending that kind of $$$

The first thing I’ll play around with is the Lean Cruise Mode tuning in the Dynamic EFI system to see what kind of gains are possible there.

Your going to have to have a turbo or turbos that spool almost instantly to have low end torque to pull 35s at 1700. It will also be very difficult to keep velocity up as the exhaust cools on its way back to remote turbos, especially using headers.

I'm not trying to be a downer, I'd love to see you accomplish your goals because diesel like numbers out of a sbc would be awesome. I'm curious about your outcome.