Aftermarket peanut tank will not fit as a direct bolt-up. The new tanks have a "tunnel" welded to the tank, which fits the backbone.
I have a 2005-2006 carb tank at home I can measure the distance between the mounting holes for you if you need it, or just measure yours.
The issue will be mounting the EFI pump/filter in the tank.
“Peter, arson is a serious crime. It's not like smuggling Oriental hookers into the country, in steel drums........” ~ Glenn Quagmire~