I have a 98 cummins, I just installed a #10 fuel plate and need to put in the boost elbow also and I'm not sure if I have the correct part out, does the stock elbow have a orface like the elbow that came in the kit or does it have a 3/16 hole. this part came off the back of the AFC housing off the tee.

 

think I figured it out on the back of my AFC housing there is a tee the boost elbow fitting replaces the 1/8 npt barbed fitting that goes to my wastegate

 

bingo!