I posted a picture of the Magnason kit. You posted the correct pump but the sock is not right. Odds are a demel would take care of that though.

 

Ok before I order this pump. I just went out and checked and make sure! I purged the line and nothing came out with my ignition switch turned forward. And I opened my blade on my TB and shot a little bit of gas in it and it didnt fire up. I did this before when I did my test fire when I first rebuilt the engine

 

where can you buy the magnuson kit? I can find it anywhere!

 

I dont think a 255 will fit in the 99-03 return style fuel system bucket without modification. I would look into the 255 assembly from racetronix. It has new electronics, walbro 255, and the jet pump so the pump doesnt starve in low fuel conditions. I have ran one for about 3 years without any issues.

Racetronix - - Fuel Module, GM SUV

 

You can fit two 255's in a return style bucket

 

Is there a drop in pump out there for returnless? I can't seem to find anything. Looking for either a 255 or 340. Im trying to spray 200 on a progressive soon and obviously it's risky with stock pump. Also: Sorry OP, don't mean to thread jack, just figured this pertained to the same info.. Any help is appreciated. Thanks guys.