Dancing is Forbidden

A few weeks back I got a code 8, tdc sensor. Changed out the distribuor, everything was fine. Then a few weeks after that I put a DX head on the car. Immediately the distributor threw code 8. Jeez. So I put ANOTHER distribuor on, Immediately again code 8. WTF?!?!?! Anyone know what might be causing this? There is also the issue of my throttle body not sweeping 100% but that is ok with me. Do you think there is a relationship between these two? Thanks guys.