Architecture
Not one universal 67–87 weldment. One rail architecture, generation-specific body hats, wheelbase on the rear clip.
Buy two sticks of A500 2×6 × 0.188 (or 0.250). Laser the front and rear clips from 3/16 plate, tab-and-slot. Year/model is weld-on hats — core, cab, later engine and trans. 67–72 and 73–87 are different hats on the same spine.
Slip-fit is a jig. Clips are a 12–16" open C that drop over the tube. A500 will not telescope through a sharp square hole. Clocking key on the tube top. Through-bolts, then weld the strap and perimeter. The truck ships fully welded.
Raised bed: bed mounts are free. Body problem is core + cab only. Split 2–4" behind the rear cab mount, in the straight rail. Keep one rail spacing. Track width is housing plus backspacing, not pinching the 2×6s.
Taped body mounts
Center-to-center. Three widths, two spans. Not one cab width.
| Station | Fusion | Width C-C | Along the rail | Vs 2×6 |
|---|---|---|---|---|
| Core support | CORE | 33.5" | datum | Rails sit here (16.75" off CL) |
| Mid / cab front | CAB_F | 42.5" | 55" behind core | Hat ~4.5" outboard of tube |
| Back of cab | CAB_R | 23.5" | 43" behind mid | Hat ~5.0" inboard of tube |
The 2×6 follows the core. Do not dogleg the tube to hit mid or cab-rear holes. Those are weld-on hats.
Still open: core vs front axle (core_x). Placeholder is −33". Tape core-bolt
to front-axle centerline when the Wilwood is on the truck. That number slides the whole
cab station set in Fusion.
Locked product
| Item | Lock |
|---|---|
| Knuckle | Wilwood ProSpindle 831-14202, 2.5" drop, 1971–1987 pair |
| Same knuckle 67–72? | Yes. New A-arms use 73–87 ball joints. Do not order 831-14201. |
| Hub | Modular / unit hub, 5×4.75 and 5×5 |
| Rear | 4-link, 22–24" lowers (20" is the floor) |
| Tire / bags | 32" OD lay-out, ~11" bag stroke |
| Rail | 2×6 × 3/16 A500, 6" tall, 2" across the car |
CPP X10 was considered and dropped because Wilwood published the print.
Wilwood 831-14202
| Dim | Value |
|---|---|
| Spindle drop | 2.50" |
| BJ spread | 9.06" |
| Kingpin vs hub face | 82° |
| Hub face to BJ axis | 3.68" |
| Tie rod reach | 4.09" |
| Tie rod drop | 2.35" |
Spine and clips
| Dim | Value |
|---|---|
| Tube | 2 × 6 × 0.188" A500 |
| Orientation | 6" tall, 2" across the car |
| Rail CL from vehicle CL | 16.75" |
| Clip overlap | 14" |
| Clip plate | 0.188" |
| C-socket clearance | 0.030" per side |
Clip is a 3-sided C plus closing strap, U-notch for tube radius. Tabs proud 0.06–0.10". Laser slot ~+0.010 over plate — freeze with a coupon.
Fusion coordinates
Origin = front axle × ground × frame centerline. +X rear, +Y up, +Z passenger. If the canvas looks empty after Run: Fit view. Rails sit 16.75" off center, not on the origin.
| Parameter | Value | Status |
|---|---|---|
| front_overhang | 34" | Estimate — horns / core |
| wb | 117.5" | Locked for first proto |
| rear_overhang | 42" | Estimate — raised bed |
| core_x | −33" | Placeholder — tape next |
| cab_f_x | core_x + 55 | Computed from tape |
| cab_r_x | cab_f_x + 43 | Computed from tape |
| rail_bottom | 8" | Ride height — bags change this |
| spine_length | 193.5" | 34 + 117.5 + 42 |
Wheelbases
Rear clip changes these. Cab hats do not.
| Body | Years | WB |
|---|---|---|
| Short 6.5' | 67–72 | 115.0" |
| Long 8' | 67–72 | 127.0" |
| Short 6.5' (prototype) | 73–87 | 117.5" |
| Long 8' | 73–87 | 131.5" |
Shared vs split
| Share 67–87 | Split by generation |
|---|---|
| 2×6 spine, clip sockets, fixture pins | Cab / core hole pattern |
| IFS and 4-link architecture | Core support / horns vs OEM clip |
| Wilwood knuckle + 73–87 BJs | Engine-to-firewall hats |
| One rail spacing (core 33.5") | Wheelbase on the rear clip |
Do not share cab holes across 67–72 and 73–87.
Front clip
Order: knuckle → travel envelope → lower inner → upper inner → rack last.
- Ground, 32" tire, spindle at ride and at lay-out (frame near ground = full jounce).
- Drop in 831-14202. That locks BJ height vs hub.
- Lower arm ~level at ride, as long as the fender allows (~14–16").
- Upper inner from BJ spread, not from the rail.
- Rack last. Tie rod same length as the lower arm and parallel in top and side view.
- Engine: pan vs K-member ~1". Pan vs ground at lay-out is the real limit.
Cab still sits on the taped mounts. 2×6 under the cab stays at mount_y. Front clip may hang below the tube. Do not kink the 2×6 for the arms. 11" of bag travel will not hide a high/low rack.
Rear 4-link
- Lower bars 22–24"
- Uppers within ~1" of the lowers
- Level or slightly downhill to the front at ride
- Mild anti-squat
- Front pickups just behind the cab
- Track width = housing + backspace, not rail pinch
Fusion file
Script folder: chassis/fusion/KTECH_C10_Chassis_Setup. Copy into Fusion My
Scripts. Preferences → Design → Default design type → Hybrid. Run
KTECH_C10_Chassis_Setup. Do not run the leftover script named C10.
| Component | Role now |
|---|---|
| 00_ORIGIN | 6" cube so a good run is obvious |
| 00_SKELETON | SK_SIDE, SK_TOP |
| 01_SPINE_2x6 | Two mirrored tubes on core width |
| 02_CLIP_FRONT | Empty — next CAD |
| 03_CLIP_REAR | Empty — next CAD |
| 04_MOUNTS_73_87 | CORE / CAB_F / CAB_R construction points |
| 04_MOUNTS_67_72 | Empty hat |
| 05_IFS | Empty — Wilwood + arms + rack |
| 06_REAR | Empty — 4-link |
| 07_FIXTURE | Empty — weld table |
Next on the Fusion PC
- Hybrid + New Design + Run KTECH_C10_Chassis_Setup. Confirm six mount points.
- Tape core to front axle. Set core_x. Re-run.
- Model 831-14202 on SK_SIDE from wilwood-831-14202.png.
- Front clip C-socket + LCA inners. Do not dogleg the 2×6.
- Rear 4-link at 22–24", step around 32" tire + 11" bags.
This is a fabrication architecture, not a stamped chassis. FEA the splice, IFS pickups, and 4-link before kits leave the shop.