Update: Since my last post in 2009, I have since switched to M/T ET Streets 295/55/17's, a Dynamic 9.5 inch converter 4000 stall, and a TQ rated at 850 cfm. On the highway @ 65 mph, around 3500 rpm, I consistently get 14 mpg through dana 60 3.73's. City is around 9. Best time of 12.003 @ 111, 408 stroker in 73 Duster, Edel RPM AL heads, 236/242 @ 0.050, .544 lift, 9.6:1 static. I can run 87 octane with no pinging, incidentally.
So with OD Gearing, maybe so!