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 495 Big Block Oldsmobile

495 Big Block Oldsmobile

With today's power levels leaving wall thickness in the cylinders can also help with power and longevity

98 Effective June 15th 2026

462 FE Ford

359 Pontiac Early and Late

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 495 Big Block Oldsmobile454 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.