When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The volume demands that 3 additional cylinders require, I would imagine. The flexfuel pumps flow a little better due to the nature of volume required in E85 applications. Generally, if you're going for 450 whp+ you're going to need to upgrade the fuel pump.
For what reason? Just swap the 450 in and be done, it can support something like 750whp on pump gas and 600whp on e85 by itself. No need to complicate things even more IMO.