An idea for better mpg on a 454 BB

[lostcause06]

Ok so here's the ordeal. I am rebuilding my 454 BB on my suburban. So here's the idea.

My 454 has 300hp and about 280lbs of tq, a weak BB by any standard and I get about 12-15 MPG which is good for me... BUT... Seeing how I have some extra money to throw in the block... What if I did some upgrades (cam,heads,rollers) which would bring me to 460HP....

So would that extra 160hp kill my mpg or make it better? Now I know the usuals "tranni type, gearing, ease of gas pedals, etc.." Let's forget about all that. Assuming everything is the same on the truck (exhaust headers gearing etc) but the BB is torqued up would it improve mpg!? Let the nonsense begin.