I hear you about milling the head. Part of the reason I was looking at the crank swap was the presence of 2 integrated head 250's in my collection, would have been nice to put the cranks to use without the added expense of a new head and intake system.

One of the reasons I was looking at E85 was its antiknock behavior. Once I pull out the pencils (OK, computer) I should be able to see what I want to do. From what I can find E85 should be OK to run up to the 10:1 area with no additives, particularly since I don't race it or tow with it (that's what the 5.3 truck is for - abuse!). Just looking for silly amounts of fuel economy in my old trucks.