Not sure where the best place to ask this, but its kind of relevant. I read somewhere a year ago that 1989-1993 Thunderbirds shouldnt use a 10% overdrive SC pulley and/or Overdrive Jackshaft pulley without making appropriate adjustments/modifications. But it said 5% should be fine (sadly, its hard to find 5% overdrive JS or SC pulleys). I bought a 7% OD SC pulley from Spinning Wheels SC but havent installed it yet. My 1991 SC has Felpro Permatorq MLS headgaskets (which is an improvement over stock, from what I understand). Should a 1991 stock SC engine with fresh headgaskets be safely able to handle a 7% overdrive SC pulley? If not, what kind of mods could I do to let my car handle a 7% (or maybe even a 10%) OD SC pulley?
Thanks in advance,
-Rick Leuce