any1 no whether the 02 sensors for the stangs above 94 r bigger than the 79-93 5.0's? im talking diameter, or r they all the same size? my friends question really

 

I believe there all 3/4 thread with a 7/8 head

 

weird b/c my friends new headers both have different size o2 sensor spaces... i think its b/c they gave him 2 different headers by mistake.. but his other concern is whether 1 5/8 inch headers and 1 3/4 inch headers.. is there much of a difference, and would they affect the way exhaust fits, for example. x/ hpipe