I recently changed the passenger side head on my 98 f150 4.6 liter. Now that I've got everything reinstalled it won't start. Motor is spinning slowly, creating a great deal of heat in battery cables. And producing a strong odor on the passenger side of the engine bay

 

I'm assuming the "odor" has a smell. Details are very important. Now the question. What does the odor smell like?

 

If it spins slowly wouldn't that mean something is causing it to spin slow? Do the speedo and tach go all the way to the maxed out and back to 0 when you turn the key to on? If so the battery is bad. If not maybe the head was starved for oil and you got parts from a locked up motor.

 

@fordfan2006 Really😃😃😃

 

 

Electric burning smell? Trace the cables from the battery, clean both ends of the cables, especially one's you removed. Bad ground somewhere? Switch a power and a ground accidentally? I'm guessing your issues lies with them.