Originally Posted by Darius' timestamp='1355266903' post='22204373

The correct answer is: "It depends on the pump."

The flow from a pump decreases as boost pressure increases. Head losses in the lines also increase as fuel flow increases, so you have to look at the fuel pump curve at the operating voltage of the car. It is safe to assume the pump is powered by 12V due to resistance in the tiny OEM fuel pump power wiring. If it is powered directly from the battery via a relay with 8 GA wire (minimum for a 30 amp draw), you can get significantly more from the same pump.

For the walbro 255 or similarly sized pump, the stock lines will probably support about 600 whp on E85. Beyond that, your pump could be running out of flow prematurely.

And if you decide to upsize the lines to -8, please go to McMaster-Carr for the aluminum tubing and not summit or jegs for the crappy, over-priced coiled-up aluminum tubing.
www.mcmaster-carr.com Search for part number 89965K52 for -8 (feed) and 89965K45 for -6 (return).