difference in plugs (pics)

[1944bgardner]

I bought a new set of plugs and when I swapped them I noticed they are different. Both are 3116's, what gives. The new ones the body is shorter. If the heat range designation is part of the actual part number then they are the same? I ran tractor for couple hours doing drive. Couldn't tell, temp got up to 170.

 

[730d se]

You have the tops lined up, line up the bottoms and they should be the same in the thread area.
Some "engineer" may have gotten a bonus for shaving off some metal.
They reduce the quality and amount of materials used and either keep the price the same or even raise it.
At some point "dumb" economics will slap many companies in the back.
These are typically actions of folks that really and truly do not know how to run a profitable busness so they cut corners and make the bottom line look like they know what they are doing.