Are 4.8l vortecs really worth it?

[rs74]

I am considering not putting the new 355 down in the short bed for this build. My ultimate goal was to find an LS1 or 2 engine or something of the like to put in. The vortecs seem to be a cheaper find. I am trying to keep mpg's in mind but at the same time want some pep. I see alot of guys doing the 5.3's and 6.0's but never hear about the 4.8. I do like to run hard at times.

The 355 will fulfill my needs for power but mileage is going to suffer a bunch. IF I can have the best of both worlds what should I consider. I have a 6.0l in my 03 2500hd and like it. Realisticlally will any of these engines get close to 20 mpg with say a 4l60e trans. I think my gears are 3.73's.
This started with the 4.8l and since it is the smallest I thought maybe it might get the best mileage.