These are high quality steel bolts, that have a black oxide coating to resist rust and work well where space is minimal (like in most header applications), the smaller Allen head allows you to get that smaller Allen wrench on the bolt to tighten it.
Mr Gasket Header Bolts
Part #: 916- Length: 0.8"
- Width: 3.9"
- Height: 5.7"
- Emissions Code: 5
- Prop 65: No