TBI 454 Build - 50 State Legal

[JCampbell]

Looking at building a TBI 454 for my C30 crew cab dually. I don't want a hot rod, but I do want to up the HP/torque numbers a bit for towing and general 1-ton abuse. However, I want something that will yield reliability and longevity. I was browsing over at TBIchips.com and I ran across this build:

http://tbichips.com/Jim454.htm

Seems like a solid platform, but I'm curious about the heads on this build. Specifically, will I still be able to run 87 octane fuel? Also, anyone have any educated guesses on what the MPGs might look like on such a combination? I was getting somewhere in the neighborhood of 10.5-11 MPG on the stock set up w/ a TH400, 4.11's and 225/75/16 tires. Not looking for Prius-like numbers, but certainly don't want to decrease from the stock MPG numbers.