Hammer FabHammer Fab — Bertram, Texas
85 IROC-Z
ALL BUILDS

1985 · In-house development build

IN PROGRESS — AVAILABLE FOR PURCHASE AS A HAMMER FAB COMPLETION

85 IROC-Z

1985
HAMMER FAB SHOP
JUL 2023 – IN PROGRESS

§ 01

THE BRIEF

Hammer Fab bought this 1985 IROC-Z on July 18, 2023 with a specific job in mind: an in-house platform to develop, test, and photograph new products on. Third-gen F-body proportions gave us the right canvas for a full steel wide body — no fiberglass, no bolt-on plastic — with molded flares built to look like Chevrolet could have shipped it that way. Chicon 3D produced a to-scale digital top three-quarter rendering to lock the proportions before any metal was cut, and an AI rendering followed around 2024 to explore the street-level stance and color direction. Underneath, it's all modern hardware: Detroit Speed suspension, an LT4 dry sump engine pulled from a 2016 Z06 Corvette, a TR6060 manual, and a 9-inch rear housing with an 8.8 center section. Brakes and wheels come from a 2019 ZL1-1LE — Brembos behind the factory 19-inch wheels. The car is in progress and available to purchase for Hammer Fab to complete.

§ 02 — Note from the shop

"Our own third-gen test bed — all-steel wide body, LT4 dry sump power, and every part on it developed in house."

§ 03 — Build journal

The updates.

A living log of every meaningful moment on this build — new photos, short notes, and the milestones worth marking.

7 UPDATES · 6 MILESTONES

Milestones

  1. JUL 18, 2023— IROC-Z purchased as the in-house development car
  2. JUL 19, 2023— The day we brought it home
  3. SEP 1, 2023— Chicon 3D rendering — built to scale
  4. OCT 1, 2023— LT4 supercharged V8 — Holley mid-mount accessory drive
  5. DEC 1, 2024— In-house stainless headers for the LT4
  6. JAN 1, 2025— Custom 3-inch stainless exhaust

UPDATE 07 / 07

Jul 18, 2023

BUILD KICKOFF MILESTONE

IROC-Z purchased as the in-house development car

On July 18, 2023 Hammer Fab bought this 1985 IROC-Z to serve as our own product development and marketing platform — a car we can prototype parts on, shoot content with, and push as hard as we want without a customer's calendar attached to it. The plan from day one: all-steel wide body fender flares, Detroit Speed suspension, an LT4 dry sump engine out of a 2016 Z06 Corvette, a TR6060 manual, and a 9-inch rear with an 8.8 center section, stopping on 2019 ZL1-1LE Brembos behind the OEM 19-inch wheels.

UPDATE 06 / 07

Jul 19, 2023

ARRIVAL MILESTONE

The day we brought it home

Pretty clean car from the looks of it. The catch: it didn't run when we bought it — the seller said it was overheating. Turned out to be nothing more than a vacuum leak, something these old Tuned Port Injection engines are notorious for. The leak leans the engine out, and a lean running condition is exactly what makes them overheat. So the seller wasn't wrong. Lucky for us, we got a great deal — and lucky for them, it found a great new home and is about to gain new life.

Loaded up and headed to the shop — an honest, straight IROC-Z.J001
Loaded up and headed to the shop — an honest, straight IROC-Z.
Evening light back at the shop. Original paint, factory 16-inch IROC wheels, louvered hood.J002
Evening light back at the shop. Original paint, factory 16-inch IROC wheels, louvered hood.
Following it home in the mirror.J003
Following it home in the mirror.
Hood up for the first inspection — Tuned Port 305 with the factory airbox still in place.J004
Hood up for the first inspection — Tuned Port 305 with the factory airbox still in place.
The Tuned Port Injection plenum. The vacuum leak hiding in here is what the seller diagnosed as overheating.J005
The Tuned Port Injection plenum. The vacuum leak hiding in here is what the seller diagnosed as overheating.
Gray cloth interior, largely intact and unmolested.J006
Gray cloth interior, largely intact and unmolested.
Driver's side — factory seats, console, and door sill trim all there.J007
Driver's side — factory seats, console, and door sill trim all there.
Rear seats and console from the passenger side.J008
Rear seats and console from the passenger side.
Original door panel with the power window switches still working.J009
Original door panel with the power window switches still working.
Hatch glass and rear cargo area — no rust, no butchery.J010
Hatch glass and rear cargo area — no rust, no butchery.

UPDATE 05 / 07

Sep 1, 2023

DESIGN MILESTONE

Chicon 3D rendering — built to scale

Chicon 3D modeled the car digitally to scale and delivered a full set of renderings. Working in 3D instead of a 2D sketch means the flare volume, ride height, and wheel fitment we see here are the real numbers we build to — hood louvers, rear window vents, quad projector headlights, the rear diffuser, and the deck spoiler all placed off the model.

Chicon 3D top three-quarter rendering — modeled digitally to scale.J011
Chicon 3D top three-quarter rendering — modeled digitally to scale.
Front three-quarter — steel flares, front splitter, and gold wheels under the arches.J012
Front three-quarter — steel flares, front splitter, and gold wheels under the arches.
Head-on — quad projector headlights, twin hood vents, and the full width of the flares.J013
Head-on — quad projector headlights, twin hood vents, and the full width of the flares.
Rear three-quarter — window louvers, deck spoiler, and center-exit diffuser.J014
Rear three-quarter — window louvers, deck spoiler, and center-exit diffuser.

UPDATE 04 / 07

Jun 1, 2024

DESIGN

AI rendering — street-level direction study

A second look at the car around 2024, this time generated with AI to see the wide body from street level with the IRON-Z graphics package, dark wheels, and a loading-dock backdrop. Useful as a mood and color study alongside the to-scale 3D work.

AI rendering — street-level view of the wide-body IROC-Z.J015
AI rendering — street-level view of the wide-body IROC-Z.

UPDATE 03 / 07

Oct 1, 2023

DRIVELINE MILESTONE

LT4 supercharged V8 — Holley mid-mount accessory drive

The supercharged LT4 gets a new Holley mid-mount accessory drive. The factory Corvette bracketry hangs the alternator, A/C, and power steering out front and wide — exactly the wrong shape for a first-gen F-body engine bay. Holley's mid-mount kit pulls everything tight to the block and tucks it in behind the front cover, which buys us the clearance we need for the wide-body front end, the radiator, and the plumbing that has to run past the engine. Kit purchased and installed here at the shop — the full install is in Episode 4 below.

VIDEO
Hammerfab IROC-Z Episode 4 — Holley Premium Mid-Mount Complete Accessory System, GM Gen V LT4.
LT4 with the Holley mid-mount drive installed — everything pulled in tight to the block.J016
LT4 with the Holley mid-mount drive installed — everything pulled in tight to the block.
The Holley mid-mount kit as it arrives — brackets, alternator, A/C compressor, power steering pump, tensioners, pulleys, belts, and hardware.J017
The Holley mid-mount kit as it arrives — brackets, alternator, A/C compressor, power steering pump, tensioners, pulleys, belts, and hardware.
Holley's reference photo of the completed mid-mount drive on an LT4.J018
Holley's reference photo of the completed mid-mount drive on an LT4.
Mid-mount dimensional drawing — the numbers we used to check clearance in the IROC engine bay, wet sump vs. dry sump.J019
Mid-mount dimensional drawing — the numbers we used to check clearance in the IROC engine bay, wet sump vs. dry sump.
CAD overlay showing how the mid-mount bracketry and belt routing sit against the LT4.J020
CAD overlay showing how the mid-mount bracketry and belt routing sit against the LT4.
Motor mount hardware bolted to the LT4 block on the stand.J021
Motor mount hardware bolted to the LT4 block on the stand.
Improved Racing EGM-132 oil filter and cooler adapter with -AN fittings.J022
Improved Racing EGM-132 oil filter and cooler adapter with -AN fittings.

UPDATE 02 / 07

Dec 1, 2024

FABRICATION MILESTONE

In-house stainless headers for the LT4

Custom stainless headers built in house for the LT4. The flanges are our own design — 3D machined stainless with an integrated boost gasket. The stainless is harder than the copper gasket, so as you torque the flange down it digs into the copper and forces it tight against the head, giving a leak-proof seal even under serious boost. Those flanges are available on our store. Tubes are 1-7/8" for max flow in the tightest possible package — and it is tight in a third-gen F-body. Collectors are billet stainless from SSCustoms out of Australia, and we used their 3D printed build blocks to iterate and visualize the tube layout. Those tools work great and really speed up this kind of precision fabrication. With the headers finished we 3D scanned them, and we're planning to offer CNC-bent stainless versions down the road. If you're doing an LT swap in your third gen, we have some solutions for you.

Our 3D machined stainless flange with the integrated copper boost gasket — the stainless bites into the copper as it's torqued down.J023
Our 3D machined stainless flange with the integrated copper boost gasket — the stainless bites into the copper as it's torqued down.
1-7/8" stainless primaries stepping off the machined flange.J024
1-7/8" stainless primaries stepping off the machined flange.
Machining detail on the flange face — port shapes and sealing surface.J025
Machining detail on the flange face — port shapes and sealing surface.
On the bench with SSCustoms 3D printed build blocks used to iterate and visualize the tube layout.J026
On the bench with SSCustoms 3D printed build blocks used to iterate and visualize the tube layout.
TIG welds and billet stainless collector work up close.J027
TIG welds and billet stainless collector work up close.

UPDATE 01 / 07

Jan 1, 2025

FABRICATION MILESTONE

Custom 3-inch stainless exhaust

The complete 3-inch stainless exhaust was cut, fitted, and TIG welded in house. The system uses V-band clamps throughout for easy service, flex joints to isolate engine movement, electric cutouts, and a one-off mono muffler tucked across the rear. We also built forward-facing resonance tubes that converge with the combined X/H-pipe section — some experimental exhaust tuning we wanted to explore on this car. Every bend and junction was packaged tightly around the TR6060, torque arm, rear suspension, and wide rear tires.

The finished 3-inch stainless system from headers to mono muffler — fully fabricated in house.J028
The finished 3-inch stainless system from headers to mono muffler — fully fabricated in house.
The experimental combined X/H-pipe section and forward-facing resonance tubes being fitted beneath the TR6060.J029
The experimental combined X/H-pipe section and forward-facing resonance tubes being fitted beneath the TR6060.
V-band clamps, flex joints, and the forward-facing resonance tubes converging at the crossover.J030
V-band clamps, flex joints, and the forward-facing resonance tubes converging at the crossover.
Full underbody layout showing the electric cutouts, dual 3-inch runs, and custom rear muffler.J031
Full underbody layout showing the electric cutouts, dual 3-inch runs, and custom rear muffler.
Electric cutouts and tight routing around the Detroit Speed rear suspension.J032
Electric cutouts and tight routing around the Detroit Speed rear suspension.
Early fabrication of the one-off transverse mono muffler and tailpipe routing.J033
Early fabrication of the one-off transverse mono muffler and tailpipe routing.
The custom mono muffler installed tightly behind the rear axle.J034
The custom mono muffler installed tightly behind the rear axle.

§ 04 — Process

Chapter by chapter.

Every build is documented as it moves through the shop. Here's how this one came together.

Chicon 3D renderingC035
DIGITAL RENDERING, TO SCALE
01CHAPTER

Chicon 3D rendering

Before any steel was cut, Chicon 3D built a to-scale digital model and delivered the top three-quarter rendering that set the proportions for the wide body, the stance, and the wheel fitment.

AI direction studyC036
DIRECTION STUDY — C. 2024
02CHAPTER

AI direction study

Around 2024 we ran an AI rendering to explore the car at street level — a second look at color, flare volume, and how the graphics package reads from the side.

§ 05 — Gallery

Frame by frame.

6 FRAMES · SHOT IN-HOUSE

85 IROC-Z — frame 1G037
001 / 006
85 IROC-Z — frame 2G038
002 / 006
85 IROC-Z — frame 3G039
003 / 006
85 IROC-Z — frame 4G040
004 / 006
85 IROC-Z — frame 5G041
005 / 006
85 IROC-Z — frame 6G042
006 / 006

§ 06 — Next steps

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