This is a NEW never USED set of GM BBC pistons. They are for a 4.280" bore motor. They. 990 pins and about 1.645 CH.
Pistons BBC 4.338" 1.15 ch Diamond 6241A100 NHRA IHRA Truck IMCA WISSOTA MUD K&N
Pistons BBC 4.589" 1.26 ch NHRA IHRA Truck IMCA WISSOTA MUD K&N
Pistons BBC 4.500" 1.65 ch SRP PN 139482 NHRA IHRA Truck IMCA WISSOTA MUD K&N #1
Pistons BBC 4.500" 1.65 ch SRP PN 139482 NHRA IHRA Truck IMCA WISSOTA MUD K&N #2
Pistons BBC 4.290" 1.350 CH Speed Pro H1134CP +040 NHRA IHRA Truck IMCA WISSOTA
Pistons BBC 4.442" 1.55 ch CP 4516 NHRA IHRA Truck IMCA WISSOTA MUD K&N
