I'm looking at buying injectors online. I found these and am wanting to know what's the difference with the ends?

 

My brother bought the exact same ones (top pic) for his truck. I have no clue what engine what the bottom pic would work on.

 

The bottom pic looks almost like some sort of 12v injector , maybe something for a non IC 1st gen, the body looks kinda big. It almost looks like that hold down nut is part of the injector body , i have never seen one like that before.

The top pic look like 24V injectors.

 

The ones in the top of the picture are the correct style to fit your truck.

 

Looking at the bottom pic...I would say they are from an early 90's 6bt motor.....We use them here...2 types....with the nut attached the inj pump is a CAV rotary..without nut the inj pump is a BOSCH..Think around the 92-93 when they changed.....