You could get this http://www.dynamicefi.com/
to use on a GM TBI and be able to switch between different fuels without reprogramming everything or need of a laptop. Kinda nice when you couldn't find E85 and need to switch back to gas.
The different modes preprogrammed on that can adjust the timing for different blends.
1975 Wagoneer DD
360 with large cap ecm controlled HEI, TBI EFI, Comp Cam 260H, Edelbrock Performer Intake, CS130 alt, 4 row radiator, S10 steering box, QT w/LO, WT 3.54 D44 axles. Rancho 9000X's, ~4" lift, Caddy rear discs.