Review on 🔩 High-Quality ARP 100-1110 1001110 Header Bolts: Hex Style Heads, Chrome Moly Steel, Black Oxide Finish - Set of 16 by Brian Messerly

I bought these for very tight spaces where a 3/8 size would fit but the wrench still had tight access. The screws appear to be of good quality and provide the extra key room I was hoping for. Disadvantages: (1) - Pay attention to their length. They are longer than the head bolts they replaced, which bothered me as I was afraid they would fail before tightening. They have arrived well for me. If you have thin manifold flanges, they may be too long. (2) - Because the screws are very long, when you tighten the head with one screw, the remaining screws cannot go through the heads into the holes. With the manifold hanging from the engine, install any bolts you intend to use with a few turns. Once they're all running you can push the head in until it hooks onto the screw and then tighten those screws. Repeat the process until the header reaches the heads.