I have Siemens Deka 60 lbs injectors, short style, I am using in a '06 4.8L Silverado with factory fuel rail. The injectors barley sit in the manifold, when the rail is bolted down, you can lightly pull up on the rail and see the o-rings in the manifold aren't seated. I see FIC has two height adapters 1/2" and 1" that'll go between the rail and injector. I believe that's what I need, I'm not sure which size to get though. I figure 1/2" will do, anyone have any experience with this?

 

I got the 1/2" adapters, and they worked, but now I got to make some spacers just a little less than 1/2" for the fuel rail haha. Oh well should be good to go now though.