GSC +0.003" Intake or Exhaust Valve Guide for Porsche 996/997 GT3 Cup – GSC3997.003-1
The GSC3997.003-1 Oversized Valve Guide is crafted for Porsche 996 and 997 GT3 Cup engines and fits either intake or exhaust positions. Produced by GSC Power Division, this +0.003" guide is precision-machined for 6mm valve stems and built to handle the demands of high-performance racing applications.
Fitment and Quantity Notes
- Standard size – available individually or in sets of 12
- Oversized options – sold individually in +0.001" and +0.003" increments
- Full engine build – requires two complete sets (24 guides total)
Technical Specifications – GSC3997
| Specification | Inches | Millimeters |
|---|---|---|
| Total Length | 1.673" | 42.49mm |
| Outer Diameter | 0.4160" | 10.57mm |
| Valve Stem Diameter | — | 6mm |
Perfect for Porsche GT3 Cup builds requiring oversized valve guides, this +0.003" variant ensures tight fitment and consistent performance under race conditions.
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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