I was browsing AdvanceAuto.com looking to see what distributors share the same ignitors, and they only sell one for AT 90/91. I clicked the whole distributor and they show different part numbers for AT and MT (TD23U and TD24U). So, what's the difference? They both use the same cap and rotor kit. I mostly need to know if I can swap ignitors (I have the one listed for AT, and I have a MT)

 

Anyone? I found a few thing that say the 23 and 24 should be interchangeable, but then why would they have made two different ones? Perhaps you can use the AT distributor on a MT but not MT on AT?