Set of 6 genuine ARP 12 point nuts to suit Holden 6 cylinder head manifold studs (202, 186, 179 etc)
Holden 6 manifolds are notoriously tight in fitment (particularly triple Weber & SU manifolds)
Use a 7/16 ring spanner instead of 9/16 with the factory nuts. Gives much greater clearance and less fouling on manifold.
Highly recommended for all triple carb setups.
3/8 UNF