If it does happen to be a direct swap that would be neat. Our 2010 5.3 is running 11 pounds on stock pump. I dont plan on going that high on my rcsb probobly 7 at most and 4 for the street cuz I gotta do 500 miles a week, and it only sees the track a couple times a year.

 

Ordering mine Friday, if not Monday next week. Need to round up some buds to lift the bed.

 

still no response

 

Holy Crap I didn't know that this thread was still alive. I was told that this pump would be a direct replacement and will support 600rwhp.

ACDelco MU1847 OE Service Fuel Pump Module Assembly : Amazon.com : Automotive

 

By who?

I ordered my flex fuel pump Tuesday after work from a salvage yard, shipped out Wednesday. Pump is out of a 2008 5.3 ex cab 6.5" bed, LC9 engine. I should get it tomorrow, then swap as soon as possible. I really really really really hope it's a direct drop in. If not I'll run the factory non flex as normal, and the flex off a hobbs.

 

 

How did it go?

 

Don't know yet, we got about another foot of stupid snow yesterday. I'll definitely keep this thread updated when I do it.

 

To my fellow go fast friends that were burdened with a factory non-flex fuel pump, I believe we're in luck!

I'm starting with a 2007 4.8 Silverado. After putting my turbo on with 80 lb. injectors and the factory non-flex pump, my fuel pressure was dipping down to 20-30 psi under nearly any boost at higher RPM.

The pump I put in was out of a 2008 extended cab short bed 5.3 flex-fuel LC9 engine Vin 3 (I believe). I bought the pump from car-part.com for $115 shipped. My brother and I put the truck on a lift, and began unhooking the straps, fuel lines, and connectors. Before fully dropping it out, he confirmed that the connectors and layout looked similar. We then removed it.



We knocked the retaining ring off, and removed the factory pump, then compared the two side by side. We noticed that the fuel level arm was the opposite way on the new pump, and shorter in length than the factory pump. We also noticed that the locating tab around the base was in a different orientation on the new one.

We had to trim about half of the locating tab so that the pump could rotate enough so that the connector you see in the lower right of the following picture could clip in with binding or breaking.




We put the green o-ring back on, dropped the new pump in, knocked the retaining ring back on, lifted it back under the truck, hooked up all the hoses and connections. Fired it up and IT WORKS! It may be a few weeks before I can test the new fuel pressure because my transmission slips under any boost right now. Once I swap in my 80e, I'll update this to let everyone know if my fuel pressure holds steady. From what I've seen from other trucks with a factory flex-pump, I should have no issues at all.

For reference, here are part numbers off my factory pump:



And the pump I swapped in:



I hope this helps others.

 

^
Great post...thank you!
:cheers: