Manley make late 2005-07 oversize valves that fit with only seat mods, 99043-2   1.625"exhaust,                99042-2    1.900" inlet, both are stock length 4.520" on exhaust & 4.425" on inlet, re-use your old collets & retainers, or Manley have a spring/retainer kit that suits up to .600" valve lift

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