Worried about blowing your cylinder head gasket? The stock head gasket generally looses it long term reliability around 50psi of boost. With an O-Ring'd head, studs and a stock head gasket, reliability is improved to about 65psi.
PDR also offers head stud kits for installing your ported or o-ringed head. These studs kits are slightly larger in diameter, as well as studs are inherently stronger by design over the traditional bolts.
O-ringing is done on each customers individual head and is not done on an exchange basis.
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