So next Spring I an considering swapping my stock c4 with stock rear gears for and AOD. I have a mildly modded 302 and I get anywhere from 11-14mpg in a mix of city and highway miles (I keep plenty of tools in the car and have a larger gas tank). I would likely keep the rear gear stock for now as what I am looking for is quieter highway cruising/better mpg/cooler running due to lower rpms. Down the road I may switch to a higher gear with something like a Truetrac.

- Does anyone else have a similar setup?

- What kind of MPG change should I expect?

- Are the conversion kits (minus trans) the way to go or should I source the brackets/linkage/crossmember myself?

http://www.cjponyparts.com/aod-conve...1970/p/AODCK2/

- Any major issues after the switch?

 

when i had the AOD in my 5.0 vert with stock 2.73 gears i got 28-30mpg. with a carb youll probably get low 20s or so

 

I have an Edelbrock performer 500cfm and a mild cam so what could I do to get up to your numbers? 2.79 is the stock gear for 68.

 

drive with a light foot lol keep it 65 mph or lower...

 

Doing 65 in a 65 zone can get you killed while passing through NJ. Plus you have to ride in the middle or every big rig will be up your butt in the right lane and they hate passing.

 

I can get 12-13mpg out of my AOD equipped 65 with a 4.11 and a small little 410 stroker

I can get get 18 out of my t5 equipped 68 with 3.25 and a warmed up 351w.

I can get 18 out of my FMX equipped 67 with a 2.79 and an anemic 302 (which I just pulled out last week and disposed of)

Caveat is obviously I drive my old cars like any other car. So I cruise at 75, pass faster, hit terrible stop and go traffic, and sometimes tend to be a little juvenile with my binary driving style.

 

I never really drive my car for the gas mileage.. I do have the AOD conversion with 3.70s though and I love when it drops down into the 4th gear. Im sure its better than what it was..

 

I think I would leave everything along initially and keep the 2.79 gear though I have heard issues due to the face that the torque converter is non locking and the rpms at highway speeds would be so low.

Based on my calculations of wanting about 2000rpm-ish at 70mph with 26in tires and an AOD a 3.40 rear gear would probably work best for me.

Obviously I am not driving the car for fuel economy but if I can get 18-20mpg I am saving something, keeping my engine and trans cooler in the summer, and I will get a lot more range. CJ Pony gave me a 20 gal tank instead of the 22 gal I paid for so I get about 17.5 gallons in before the click at the pump.

227.5 miles per fill up @ 13mpg
315 @ 18mpg which is basically a one way trip to my town in PA from NYC.

 

I ran the 2.79 gear for a while with my Aod, it would really drop low, almost so that I couldnt hear the engine over the highway. When I did have that in, I would just keep the car in D. so that it wouldnt drop into over drive when driving around town. My 3.70's seem a little better than the 2.75 were on the highway, with a lot more pep to get up to speed. So less bog on the engine at low speed or pick up = less fuel consumption.

Plus if you are on the highway with the 2.75s in OD its possible that you will be pulling more fuel while it bogs the engine at a low RPM.

I love cruising at 45mph in OD and then dropping the hammer, it shifts to 2nd, then 3rd and back to OD when I let off.. Its just different than the ol-3 speed.

As far as the kits.. You may be able to source out parts for cheaper, especially if you start now. Ebay is your friend, especailly for the AOD TV cable, and adapter for your specific carb. Some people swear you need a pressure gauge to set the TV pressure. I didnt.. You will have to make your decision on that one. An AOD swap is typically done for under $500 if you are crafty.
Some good info: http://www.1969stang.com/mustang/for...hp?t=63&page=2

 

MPG shouldn't be the driving factor in making this decsion. You'd have to buy a whole lotta gasoline before you'd recoup the money you're about to spend.

I have 3.70 gears in my '67. At 60 MPH, I was turning 3000 RPMs. Even my wife, who is NOT a gearhead, commented, "shouldn't this car shift again?". After installing the AOD I now turn 2000 RPM at 60 MPH - much better.

I'd also recommend buying a pre-assembled kit, specifically this one:

http://www.transmissioncenter.org/cl...conversion.htm