I didn't see it mentioned here but Passon has an OD gearset for the iron 833s that has optimized ratios for 1,2 and 3 and an OD.
I don't know much about it (ratios or anything), but caught a ride in an Ebody with one. The guy compared it to a wide ratio torqueflite with an OD. 3.91s, 26" tires and cruises at 80 at a reasonable RPM.
The guys has about $3K in the clutch and trans. Did all the work himself and commented that there is really no fuel savings as he just drives faster.
