Manual Transmissions

Unique Bellhousing: Atlas 4/5/6 family has unique bolt pattern - not shared with any other engines

Unique Ring Gear: 161 teeth (not standard GM)

Unique Starter Position: High on left side of engine

Good News: Dowel pins match GM V8 pattern, making adapters possible

AR5 / MA5 (Aisin) - Best Choice

Advantage: Bolts directly to LL8 - no adapter needed

Source: 2004-2012 Colorado/Canyon I4/I5, 2007-2010 H3 3.7L

Strength: Handles stock LL8 (275 hp), survives 400+ hp in 2WD builds

Shifter: Same location as T5/early NV3500

Output: 27-spline matches classic GM (TH350, Muncie)

Clutch: 10.5" (1986 Camaro 5.0 pattern)

Note: Solstice/Sky version has improved 2-3 ratio but requires bellhousing swap

Other Options (Require Adapters)

T56 / TR6060: 450+ hp capability, bulletproof ($1500-3000 used)

NV3500: S10, Silverado 4.8/5.3 - handles stock LL8 power

AX-15: Jeep Cherokee/Wrangler - essentially same as AR5

T5: Limited to 300 lb-ft, budget option only

Flywheel Options

Ring Gear: 161 teeth | Clutch: 10.5" | Input: 26-spline, 1.125"

Pilot Bearing: LS roller (Timken 57080)

Recommended: Emtech Motorsports Gen 2 - Link - 29 lbs, balanced with ring gear installed, drilled for 10.5" SBC clutch

Performance: Atlas Industries Chromoly - 17.2 lbs, 4140 material (~$415), lighter for higher RPM

Best OEM Clutch: 2007-2010 H3 3.7L

Budget: Aftermarket 10.5" SBC clutches work and are cheaper

CRITICAL: Pressure Plate Installation

GM 10.5" pressure plates use shoulder bolts, NOT dowel pins

Required: ARP 130-2201 pressure plate shoulder bolts

Why: Centers pressure plate on flywheel - prevents severe imbalance

Never: Use standard hardware store bolts

Adapter Options

No Adapter: AR5/MA5 from Colorado/Canyon/H3 - bolts directly

Adapter Required: T56, TR6060, NV3500, T5, AX-15, all others

Why It Works: LL8 dowel pins match GM V8 pattern even though bolt holes don't

Recommended: FabBot 4200 to LS Adapter - Link - Allows use of T56, TR6060, and other LS transmissions

Alternative: Atlas Industries - Billet aluminum adapter (Atlas 4/5/6 to SBC/LS/BOP)

Custom Option: 0.5"-0.75" aluminum plate, maintain input shaft depth