Steel 4-Bolt Main Caps for Pontiac 421-428-455 with Dowel Pins(Set of 3) by Butler Performance CNC Shop *BLOCK MUST BE ALIGN BORED AND THRUST MACHINED*
Billet steel main caps machined right here in our CNC Shop.
Added notches on each end for ease of removal
Designed and tested in our own blocks and engines by our master machinists
ARP Main Stud Kit Recommended- Part# ARP-194-5601 or OPT-194-5601-220K
ALL aftermarket billet main caps require line boring and require the thrust surface to be machined to match your particular block
