The BETTER option. Our ARP 8740 Chrome Moly intake manifold bot kits are black oxide coated for good looks and corrosion resistant. They are rated at a minimum 170,000 PSI, which is even stronger than a grade 8 bolt! They also feature a reduced diameter hex head for easy intake manifold changes and less clearance problems with oversize runners. Matching black oxide washers (shown above) are included.