Wilwood - Iron GM Metric Single Piston Calipers

Wilwood – Iron GM Metric Single Piston Calipers

The Wilwood Iron GM Metric Single Piston Calipers are all-new, purpose-built racing calipers—not rebuilt OEM units—designed as a direct bolt-on replacement for 1978-and-later GM Metric calipers commonly used in spec racing categories. These calipers combine new-part quality with modern machining precision for reliable braking performance.

Wilwood’s 2.50" piston GM Metric caliper is officially IMCA approved as an OEM replacement and meets all rules for Modified, Stock Car, Hobby Stock, Northern Sport Mod, and Southern Sport Mod classes. Additional 2.75" and 2.00" piston options are available for non-restricted classes and custom brake bias tuning.

Unlike re-machined OE castings, Wilwood engineered three dedicated castings, each designed specifically for its piston bore size. This eliminates compromises in strength and reliability while allowing racers to properly tune front-to-rear brake bias.

Each caliper features a stainless steel piston to resist corrosion and slow heat transfer, along with high-temperature bore seals for long service life and positive piston retraction.

Note: Calipers require hardened Wilwood slide pins (sold separately). Use Wilwood Slide Pin Kit PN 230-0619.

Features & Benefits

• All-new cast iron calipers – Not rebuilt or re-machined
• IMCA approved (2.50" piston) – Legal OEM replacement
• Multiple piston sizes – 2.75", 2.50", and 2.00"
• Dedicated castings per bore size – No strength compromises
• Stainless steel piston – Corrosion resistant, reduced heat transfer
• High-temp bore seals – Long life and positive retraction
• Bolt-on GM Metric replacement – Ideal for spec racing

Fitment & Specifications

• Caliper Type: Single piston
• Material: Cast Iron
• Piston Sizes Available: 2.75" / 2.50" / 2.00"
• Mount Center: 5.46" (GM Metric)
• Weight: 4.3 lbs
• Inlet Thread Size: M10 x 1.50
• Application: GM Metric (1978-up), spec racing
• Slide Pins: Required, sold separately (PN 230-0619)