S&S Cycle Crankcases — Harley-Davidson Electra Glide, Electra Glide Classic, Electra Glide Ultra Classic (1955-2026)

S&S Cycle MK-Series crankcases for Harley-Davidson Touring with Milwaukee-Eight engines, engineered to support larger-displacement builds up to 4.5" bore. These cases feature a redesigned 4.695" spigot bore, machined oil scraper, and large-volume sump for improved reliability under high-output power without requiring frame modifications.

Features

• 4.695" spigot bore accepts cylinders up to 4.5" bore
• Machined, close-fitting oil scraper for better scavenging than stock cast cases
• Stock deck height — maintains OEM geometry
• Large-volume oil sump for improved cooling and reliability

Specifications

• Brand: S&S Cycle
• Manufacturer Part #: 310-1341
• Category: Engine Components / Crankshafts
• Weight: 31.65 lb

Fitment

Fits Harley-Davidson Touring models with Milwaukee-Eight (M8) engines.

Frequently Asked Questions

Will these cases support a 4.5" bore cylinder kit?

Yes — the 4.695" spigot bore is designed to accept cylinder kits up to 4.5" bore, enabling big-displacement builds.

Do I need to modify my frame to install these?

No — these cases use stock deck height and install without frame modifications.

How do these differ from stock Harley cases?

The machined oil scraper reduces windage loss and scavenges more oil than stock cast cases, improving cooling and reliability at high output.

What engines do these fit?

These are designed for Harley-Davidson Touring models with Milwaukee-Eight (M8) engines.