Pontiac Grand Prix GXP
The Grand Prix GXP is the technical peak of the nameplate’s front-drive era: a 303-hp LS4 V8 combined with specific brakes, suspension, steering, wheel/tire sizing and electronics rather than a simple engine swap.
More chassis than badge engineering.
- LS4 5.3L aluminum V8
- 4T65-E HD family transaxle
- Performance suspension
- Larger brakes and GXP-specific hardware
- Stability-control and steering upgrades
- TAPshift-style manual control
LS4 power comes with LS4-specific homework.
Engine mounts, transmission health, cooling, oil consumption/leaks, cylinder-deactivation hardware and tight engine-bay packaging deserve careful inspection. A well-sorted stock GXP can be more rewarding than a modified example with deferred maintenance.
Master Customs prioritizes factory-era documentation and period road tests, then uses established enthusiast references for service and ownership context. Equipment changed by model year and RPO; verify a specific car by VIN/RPO and factory service information before ordering parts.