Any one know what size the stock pump is in an '05 ss?

 

I dont have exact dimensions but here is a pic.

Stock on the left, walbro 255 high pressure pump (GSS342) on the right

 

is that a direct replacement,

oh and bolus, we are playing with the Atom as we speak

 

Who's atom are you working on? Silvers? He said he was working with a tuner from here.

I had to trim the swirl pot bucket thing to get it to fit. About 20 seconds with the dremel

See the plastic lips that keep the walbro pump from sliding into place? I just carved those off with the dremel. Then I had to solder on a new connector but it was an easy replacement