darkirish63

iTrader: (5)

Its going to stay NA for a while so the 255 it is. Now to try and figure out the piston conundrum.

mcfarlnd

iTrader: (15)

I bought this and actually called them before hand. I asked if it was really a "drop in" they say yes, I have lots of doubts because it's been tried on here a lot. Either way, for the price, it is a genuine pump and comes with the correct type of fuel line needed (not the rubber type). My truck is a 07NNBS though and haven't installed it in the bucket. The one thing for me is that it does not have the second port for the Venturi. I will have to figure out how to fill the bucket without coming off the pressure line for the Venturi. This will be my project for next week.

darkirish63

iTrader: (5)

Let me know how the pump works out. I'll be using the Holley 255lph drop on replacement for now and keep the 450 on hand for when I boost the truck next season.

Vortec350ss

iTrader: (20)

I was able to keep idle pressure in line with the venturi mods as Pat mentioned. The problem was that the returnless system limited the capability of the 450 pump in a major way. I lost fuel pressure long before the pump was capable of pushing through a return system.

Take it from me, someone who has been there, its worth going return style.

gearheaddrew

The Holley 12-954 comes with a Walbro 450 / F90000267 pump. It is called out as a 255LPH pump on because it is only rated for NA - 550hp. This module is produced by TI Automotive who bought Walbro 15 years ago.

This horsepower rating is limited by the refilling jet/venturi system not the avaliable pump output.

darkirish63

iTrader: (5)

Good to know - since I'll be staying NA at or around 500 for now I'll feel better about replacing the stock pump either way since it has over 180K miles on it :>)

rpm-inc

I bought an aftermarket chinese returnless module on ebay. Removed the pump, regulator and filter. Installed the 450. Gonna run it through a fuelab regulator located near the tank with a return on top (bulkhead fitting) into the bucket. Post pump filtration through a spin on filter. Hot wired of course.

Can't see how it won't work. Ill let you know in a week or 2...

03sierraslt

iTrader: (22)

Why not just run a real return system and eliminate the shortfalls?

darkirish63

iTrader: (5)

​​​​​​​So, if I remove the Venturi at the bottom of my '04 bucket as shown in your video, do I need to do anything else to run the 450?

rpm-inc

Doing it as cheap as possible with parts I have laying around. What are the shortfalls?