Wilwood 120-9729 Narrow DynaPro Lug Mount Disc Brake Caliper Mount - 4-Piston 3.50

The Wilwood 120-9729 Narrow DynaPro (NDP) lug mount caliper is a stress-flow forged, four-piston disc brake caliper engineered as a direct performance upgrade over the popular Narrow Mount Dynalite (NDL) series. Featuring a 3.50" lug mount pattern, dual piston sizes of 1.38" and 1.25", and a black anodized aluminum body, this caliper delivers superior clamping efficiency, reduced pedal travel, and outstanding stopping power for race and high-performance street applications.

Stress-Flow Forged Construction:

Unlike calipers machined from straight-grained billet blocks, NDP calipers are stress-flow forged from premium-grade billet aluminum. This process realigns the metal's grain structure within the contour of the caliper body, producing a significantly stronger finished part. The FEA-optimized body design incorporates a fortified radial transition between the piston housings and bridges, eliminating the stress-concentrating steps and shoulders found in older designs. Center bridge bolts add further resistance against caliper body separation over the center of the pads.

Key Features:

• Mount: 3.50" narrow lug mount — direct upgrade/replacement for Narrow Mount Dynalite (NDL) series
• Pistons: Four pistons — dual 1.38" and dual 1.25" heavy-wall stainless steel
• Fluid Inlet: 1/8" NPT inlet port
• Pad Type: 7816-type brake pad, top-loaded via Quick-E-Clip retainers
• Bridge Protection: Replaceable stainless steel SRS bridge plates resist pad gouging and extend caliper service life
• Bleed Screws: Four-corner bleed screws for simplified bleeding in any mounting orientation
• Fluid Passages: Fully internal — no external tubes or hoses
• Finish: Black anodized aluminum body

Performance Advantages:

• Reduced structural deflection and lower fluid volume displacement translate to a firmer pedal feel with less travel
• Heavy-wall stainless steel pistons resist corrosion and slow heat transfer from the pads, protecting hydraulic fluid integrity
• Spring-loaded SRS plates eliminate pad rattle and dampen vibration harmonics that contribute to brake squeal
• Quick-E-Clip top-loading pad retainers allow rapid pad service without caliper removal
• Slimmer bottom profile (no lower pad supports) provides improved bottom-side clearance for tight-clearance mounting applications

The Wilwood 120-9729 NDP caliper is backed by Wilwood's rigorous structural deflection and volume displacement testing, confirming the efficiency gains of its innovative forged design. It is an ideal choice for dirt late model, circle track, and performance street builds requiring a reliable, high-clamping narrow-mount caliper.