6125-4160 400 - 4.210 Stroke Pontiac Late FX Series -18cc Dish Top Pontiac Late Forged Piston Set 4.160 inch bore Pin Dia.: 0.98" Comp Height: 1.48" Piston Series Option:FX-1 4032 Alloy 366 Chevy LS

366 Chevy LS

360 Chevy LS

more than that and it would have been more cost effective and better to replace the whole set

406 Pontiac Late

6125-4160 400 - 4.210 Stroke Pontiac Late FX Series -18cc Dish Top Pontiac Late Forged Piston Set 4.160 inch bore Pin Dia.: 0.98" Comp Height: 1.48" Piston Series Option:FX-1 4032 Alloy 366 Chevy LS458 Pontiac Late , FX, Comp Height: 1. 48, 18cc Dish Top, PIN: . 98", Full Floating or Press Fit, Ring Groove: 1. 2 1. 2 3MM, Stroke: 4. 210", ROD: 6. 625, Approx Comp Ratio: 62cc 11. 54, 87cc 9. 24, 124cc 7. 22 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.