Tired of loosing your time honing and fitting valve guides? Here is why AV&V reamers are now used by the top cylinder head shops in the industry. Designed by AV&V for use with manganese bronze material, these special reamers feature a unique design and a longer pilot for a perfect alignment with the valve guide while reaming. You will ream a valve guide to exact dimension without any taper in 4 to 5 seconds only. Guides will last longer than with the honing method because there is no crosshatch left after reaming. One size allows you to fit both intake & exhaust if you use AV&V valves & guides. Note: These reamers are for Manganese bronze only, do not use with cast iron guides.