GSC Intake or Exhaust Valve Guide for Porsche 996/997 GT3 Cup – GSC3997
The GSC3997 Valve Guide is designed to fit either the intake or exhaust side of Porsche 996 and 997 GT3 Cup engines. Manufactured by GSC Power Division, this standard-size guide is precision-machined for 6mm valve stems and is ideal for high-performance engine builds.
Fitment and Quantity Notes
- Standard size – available individually or in sets of 12
- Oversized options – sold individually in +0.001" and +0.003" sizes
- Complete engine build – requires 2 full sets
Technical Specifications – GSC3997
| Specification | Inches | Millimeters |
|---|---|---|
| Total Length | 1.673" | 42.49mm |
| Outer Diameter | 0.4160" | 10.57mm |
| Valve Stem Diameter | — | 6mm |
Whether you're refreshing a GT3 Cup head or building a full race motor, GSC’s standard valve guide offers reliable fitment and long-term durability for intake or exhaust use.
Fitment:
- 2000-2005 Porsche 996 GT3 Cup (Intake & Exhaust)
- 2006-2012 Porsche 997 GT3 Cup (Intake & Exhaust)
Note: These guides are compatible with both intake and exhaust positions. A full engine rebuild typically requires 24 guides total (12 intake + 12 exhaust), so two sets of 12 are recommended.
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