Originally Posted by
Ken Blythen
I had an AOD in my F250 for three years then swapped it for a C6, with no change in gas mileage - but I didn't use overdrive with the AOD (60mph local limit, so rpm's were too low in od).
If you intend to still travel at 55ish, & your axle/engine combination is suited to that, the AOD won't be any advantage; & with planning to tow in the future, it would be a liability IMHO.
A C6 is much better suited to that role. AOD's can be made more durable but not cheaply.
What he said x 2. But, if you are getting 10 MPG at 55 MPH with the 351HO and a C6 there is some kind of a problem. I had an 82 351W with a C6 and 3.50 gears that got 13 on the highway at 62 MPH, and would have done better at 55. So, long before swapping to an AOD you should figure out what the problem is. Low MPG may be a fuel problem, like a blown power valve on the Holley or the choke being stuck on, or it may be that the ignition timing is off, as in the initial lead or the vacuum advance may be blown.