GM LS1 Water Pump & Thermostat Housing Bolt Kit - Black Finish

GM LS1 Water Pump & Thermostat Housing Bolt Kit - Black Finish

Upgrade your GM LS1 water pump and thermostat housing with a purpose-built bolt kit crafted from 8740-grade steel and finished in a durable black coating. Featuring 12-point head bolts for increased torque and a secure drive, this kit is designed to withstand engine vibrations while maintaining a clean, professional under-hood appearance.

What's included

• 2 Short Bolts — Under Head Length: 20mm; Head Diameter: 11.65mm; Thread: M6 x 1.00mm; Spanner Size: 8mm; 12-point head; Material: 8740-grade
• 6 Long Bolts — Under Head Length: 80mm; Head Diameter: 15.20mm; Thread: M6 x 1.00mm; Spanner Size: 10mm; 12-point head; Material: 8740-grade
• 2 Small Washers — Outside Diameter: 13.65mm; Inside Diameter: 6.50mm; Thickness: 2mm
• 6 Large Washers — Outside Diameter: 16.85mm; Inside Diameter: 8.30mm; Thickness: 2mm

Key features and benefits

• Black finish adds corrosion resistance and a cohesive look with the engine bay styling.
• 12-point head bolts provide improved torque transfer and a secure fit, reducing the risk of cam-out during installation or service.
• 8740-grade steel delivers robust strength to handle thermal cycling and engine vibrations in LS1 applications.
• Precisely sized under-head lengths and diameters ensure proper seating and clearance when mounting the water pump and thermostat housing.
• Includes washers in two sizes to distribute load evenly and help maintain reliable sealing and fastener performance.

Specifications at a glance

• Compatible with GM LS1 Water Pump and Thermostat Housing
• Material: 8740-grade steel
• Finish: Black
• Head type: 12-point
• Short bolts: Under Head Length 20mm; Head Diameter 11.65mm; Thread M6 x 1.00mm; Spanner 8mm
• Long bolts: Under Head Length 80mm; Head Diameter 15.20mm; Thread M6 x 1.00mm; Spanner 10mm
• Washers: 2 small (13.65mm OD, 6.50mm ID, 2mm thick); 6 large (16.85mm OD, 8.30mm ID, 2mm thick)