Tranny comparison question

[spartman]

This one has been bugging me for awhile.

I know that manuals use less hp vs an auto.

What I am wondering is this.

Which would use less hp and require the least maintenance:

1) A ford AOD with a .67 od
or
2) A ford SROD manual with a .80 od

I have run some numbers through various calculators and it looks almost like a draw as far as rpms are concerned.

The AOD will turn lower RPM's at cruise, but when you figure in the parasitic loss because it is an auto it almost balances out with the .80 manual.

I read on one website that even though the AOD/any auto for that matter use more hp they will cost less in the long run vs a stick.

HELP!!!!

[REDNECKMOBILE]

My vote would go to the manual O/D. The trick is getting the engine to maximize efficiency at the RPM's and speed you wish to run, O/D in itself will not help gas mileage, it just gives you the ability to gear for a good launch and at the same time not over-rev the motor on the interstate, I think!

[willowbilly3]

What redneck said. overdrive alone may not increase milage if the engine doesn't have the grunt in the lower rpms to keep the truck rolling. For instance you will have to push the gas a lot harder to maintain speed on hills, even small ones. I have owned a few 5.0 with AOD and those things can smell a hill before you even see it. They are really flat in od and the shifting habits of them become rather annoying at times.

[spartman]

I guess I should also state that the tranny is going behind a 240 6 banger with 3.70 gears.