I have a 289 with a C4 that is leaking badly. I am thinking about putting in a AOD. Would like to here from others who have done this and how happy they are about the switch. Also what AOD brand they have. I use the stang for long drives most of the time. The engine has been rebuilt and has appx 300 hp

 

You can drop your old C4 off at my house.

I still like C4 because easy to rebuild and reliable.

Can't brag about mileage though.

 

I'm in the middle of my C4>AOD swap and plan to drive hwy. and do some strip/open track/ autoX whatever i find time and have fun at. I picked up a new built AOD cheap off craigslist and had my local shop put better clutches in it and give it the once over. I also installed a custom valve body that is programmed better for our lighter cars for shift pattern. I can also lock out OD if I want if I'm at the strip. If you're just doing street duty and hwy. a stock one will probaby do, just get the later years model as they improved them over the years just before AODE came out.

The nice thing is that you can up your rear gears quite a bit and still be hwy friendly. I have 3.50:1 now but may opt to go 3.73 or 3.89 after I drive it a while and see where my hwy RPM's are and how short my 1st gear shift is. I'm installing a 2200-2500 stall for street duty, it may go up later too.

It's heavier and wider than the C4 so you'll need to redo your exhaust probably to fit around it and you 'may' have to shorten/lengthen your driveshaft depending on which tailshaft your AOD has, rearend housing. There's too many variables to give a one size fits all measurement.

I'm looking forward to not being >3K RPM's at 70-80mph keeping up with traffic!
Jon

 

The AOD is a good transmission and can easily be built to take 300 - 400 hp. The problem is that when using a carburetor you must use lower gears to keep the carb out of the idle/off-idle circuits when cruising down the road at 60 - 80 mph. With your 3.50 gears at 3000 just putting in the AOD will bring the rpm down to 2000 at the same speed and lower because of the converter lock-up feature. Now you are in the Off-idle circuit where mixtures are quite rich and the rpm is below your power band so the amount of throttle needed opens the power valve and the mixture is even richer. So much for good mileage. You need at least 3.9x and 4.11 is perfect with stock tire sizes. That will keep the carb in the main metering circuit when cruising at 60 - 80 mph. Overdrive will engage at 50 so you will get good mileage and below that speed the converter lock-up functions to lower the rpm from what it might be with the C4.
there are some mods that I would recommend for any AOD and they include:
A or A+ OD servo (one of the weakest links)
a "Power Pack" kit (it increases the number of clutches in those spots that would otherwise suffer early failure)
a constant pressure valve body (it eliminates the need for a throttle pressure cable)

 

I have 3.70 gears in my differential. At 60mph I went from 3000 rpm to 2000. Driving at highway speeds is a LOT nicer.

These guys sell a conversion kit.

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

I also had to have my driveshaft shortened 1 inch.

Headers are an issue. Since the AOD is wider than the C4, my header flange (where the header bolts to the exhaust pipe) touched the transmission pan. That also happend to be exactly where the TV cable bracket mounted to the transmission. I wound up having the flange cut off the header and welded to the exhaust pipe. If I were to do it again, I'd buy shorty headers like these:

http://johnsmustang.com/Catalog/631/

 

if you have a choice id go with a 4r70w instead yoll need a transmission controller but the gear ratios are way better and its a lot stronger

 

With an AOD I'd modify the existing cross member, with the 4R70W (which the mount is 1" back) the ron morris uni-cross fits perfectly. Bauman controller is around $500. If you decide on the 4R70W make sure it has the windsor bolt pattern, mine came out of a V6 van.

 

i think the v6 mustang is the one most people go with...ive got a 4r70w laying in the back yard

 

Jonk67 -- What valvebody did you purchase. I have been wanting to change my valve body to change the shift pattern and have the OD lockout but lentech wants $500 for theirs.

 

Other than the F3UP tail (long) on the van version is there really a difference? Beggars can't be choosers and when its free I took what I could get