Difference between 73 and 74 carb body?

[TAlber8]

Is there one? A set on eBay with now bowls or slides, will all of the parts from my 74's transfer over?

 

[5twins]

The carb bodies were changed internally in '74. The floor height below the slide was dropped. That required a change in needles and needle jets. That means those two parts at least won't swap into the '73 bodies. According to the Australian club website, the '72-'73 float bowls were unique and only fit those years so your '74 bowls may not swap either.