* Stock length & head diameter
* Extreme Duty
* High Flow
* one piece forged racing grade stainless steel alloy.
* Liquid nitriding process creates a valve that is smoother and stronger than O.E.M.
* Stems are centerless ground for a longer life
* 45o angle below the lock groove to facilitate the valve seal installation
* Replaces OEM # 18031-86
Head Dia = 1.590in.
OAL = 4.550in.
Stem Dia = 5/16in. / 0.3108in.