when i had my distributor out i thought it was solid,several shadetree mechanic friends said (ain,t nothing wrong with dat,put it back in).finally took it to advance auto parts,mainly for the 1$ core charge(yes im cheap)and i took a moment to compare the rebuilt unit to my core,and i could feel the difference imediately.put the rebuilt motorcraft distributor in and what a difference!.80.00 bucks well spent.150,000 miles on previous distributor.