Shifter base for HM290 or 5LM60 swap from 1988-1992 C/K GM full-size truck
*** For OE replacement see the complete kits instead. ***
Shifter base for custom conversions using HM290 (1988) & 5LM60 (1989-92) transmissions sourced from:
- 1988-1992 Chevrolet & GMC C/K 1500 full-size trucks (GMT400)
- (GM RPO MC0)
- NOT FOR USE IN THESE VEHICLES - see complete kits
- Does NOT FIT ANY NV3500, NV4500, or S10 models - see separate listings
- Configured for shifter cup receptacle height of 7/8 - 1 1/4" as original to these models
- IF transmission was rebuilt or replaced, it MAY REQUIRE A DIFFERENT BASE. If you install the wrong one it will not work properly and could cause damage. Height can only be confirmed by removing shifter base and measuring transmission as shown in last pic.
A Hurst stick is required (NOT included, sold separately). Other brands and homemade sticks are discouraged. Stick mount has 3/8"-24 threaded holes spaced 7/8" apart on center + mating serrations for a Hurst stick on one face. Due to larger mounting threads (3/8"-24), sticks that use 8mm mounting bolts (most OE, "non-TKO" Lokar, others) will not work. Lokar TKO sticks can be mounted but only to the smooth side of the stub. To select the proper parts:
- Wait until new transmission is installed to buy shifter parts
- Remove existing shifter base if present
- Sit in vehicle, in driving position, with all interior trim (dash, console, etc) in place
- Define desired knob location in space (neutral position):
- Measure height from base flange to desired knob location = overall height
- Measure side & rear offsets from receptacle bore to desired knob location
- See this diagram for clarification
- Study the Hurst stick page for shapes that meet your needs
- Allow 3-6" for stick mount height
- Choose a stick and see what fulcrum heights are compatible with it (see chart)
- Check overall height (see chart: stick height + mount height = overall height)
- Confirm chosen combination achieves desired knob location and that fulcrum height works with stick length selected
- Consider various stick & stub combinations to optimize
- Note long sticks on angled mounts will strongly offset knob to left (can be 5-6"+)
- Note OE dust boot is short and exposes stick mount which helps in tight situations
Stub fulcrum height options (critical to optimizing leverage for short throw):
| Option | For stick length | stick mount height | stick mount angle | boot type | upcharge |
|---|---|---|---|---|---|
| A | 12" | 5.1 | vertical | Billet Plus | default |
| B | 15" | 5.6 | vertical | Billet Plus | +$10 |
| C | 15"+ | 6.6 | vertical | OE (short) | +$20 |
| D | 17"+ | 7.4 | angled 14 deg left | OE (short) | +$30 |
| G | 10" | 5.5 | angled 11 deg left | OE (short) | +$10 |
| H | 8" | 5.0 | vertical | OE (short) | +$10 |
- Stick length = point-to-point distance from mount hole to knob thread
- Stick mount height = distance from base flange to stick bolt hole (affects knob height)
- Fulcrum height = distance from lower ball to fulcrum pin; varies by option, not published
- Warning: Follow stick length guide to avoid excess effort & component failure
Kit includes pre-installed OE lower pivot cup, mounting hardware, dust cover boot, and instructions. The base is built by Core Shifters using proven Hurst Billet Plus components inside a custom housing. This kit has many superior features & components, integrated into a unique, exclusive assembly:
- Forged heat-treated billet steel gear selector stub
- Hardened steel cross-pin & stainless steel fulcrum pivot ring
- Self-centering cross-gate bias springs with heat treated spring seats
- Glass-reinforced polyamide fulcrum socket with steel wear clips
- Rubber oil control seal with steel retaining ring
- Extruded aluminum housing with Spirolox steel support ring
- Zinc-plated laser-cut steel cover with heat-treated spring retainer straps
- CNC-machined billet aluminum base
- Vibration-resistant serrated flange head steel retaining bolts
- Rubber dust cover boot (style varies)
- High quality & outstanding value!
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