6135-4125 455 - 4.250 Stroke Pontiac Late FX Series -18cc Dish Top Pontiac Late Forged Piston Set 4.125 inch bore Pin Dia.: 0.99" Comp Height: 1.285" Piston Ring Kit Option:Pistons - Pins and Locs Without Rings 325 Gen 5 LT Direct

325 Gen 5 LT Direct Injection

408 Big Block Oldsmobile

452 Small Block Ford 351W

98 Effective June 15th 2026

495 Big Block Oldsmobile

6135-4125 455 - 4.250 Stroke Pontiac Late FX Series -18cc Dish Top Pontiac Late Forged Piston Set 4.125 inch bore Pin Dia.: 0.99" Comp Height: 1.285" Piston Ring Kit Option:Pistons - Pins and Locs Without Rings 325 Gen 5 LT Direct454 Pontiac Late , FX, Comp Height: 1. 285, 18cc Dish Top, PIN: . 99", Full Floating or Press Fit, Ring Groove: 1. 2 1. 2 3MM, Stroke: 4. 250", ROD: 6. 8, Approx Comp Ratio: 62cc 11. 47, 87cc 9. 18, 124cc 7. 17 Effective June 15th 2026, These Pontiac ring grooves have been updated to the new specifications of 1. 2 1. 2 3mm. Parts manufactured prior to this date feature ring grooves with dimensions of 1 16 1 16 3 16.