I know the flexplate in AOD is same number of teeth as my C4, but I'd have to use the lighter weight C4 flexplate in the AOD, as well as my starter.

I have found AOD conversion kits for 351M so it will bolt up to the block.

What I don't know is what other modifications would be required as far as driveshaft length and if any modifications are required for the transmission cross member or if it will work as is.

Right now I'm in the midst of a frame off restoration.

The 351M and 400 are big block bell housing patterns. I don't know how someone had put an AOD behind one, but the only small block pattern came behind the earliest 400 block.

The AOD requires a TV cable or rod, which connects to the carburetor at a linkage similar to the kick down rod of older carbs. But it is a special geometry required, to provide the proper pressure rise of the ATF as the throttle is opened. At idle the test pressure, at the special test movement(throttle is forced open slightly by a special tool(chunk of steel the same thickness as an "X" bit)), it has to be 33psi right there. I think the spec was 30-35psi or close to that, I recall 33psi being the right point.

So figure out your block to trans bolt pattern first. If they can be connected, then the TV cable is the only hard part. The AOD uses the same flex plates as any later cars, from 1980-2001. Those are all interchangeable, except for the balance. You will have to have the early flexplate, which is 28oz imbalanced. The 50oz began in 1985 I think, but it overlapped years because Ford didn't change everything at once. Lo-po 302 models of 1985-1988ish would be the old firing order, and the 28oz balance I believe.

AOD's use the newer small starters, which are vastly better than the old large type. If you go to the AOD, make the starter the ring terminal trigger terminal version(or convert it). The first used spade terminals, which had corrosion issues eventually. That's an easy thing to update.

the crossmember should be the least of your problems if there are multiple hole locations in the frame mount tabs,

or both transmissions may even use the same crossmember location?

i would calculate driveshaft length when you have both transmissions and the adapter kit side by side. the AOD will also need a 31 spline slip yoke.

i'm pretty sure you'll be shortening the shaft so just a cut & balance, swap the yoke w/ new joints will get that done.

the flexplate needs to do 4 things right; tooth count, balance weight, converter stud bolt pattern and offset

you're correct in that your C4 should be the same 164 tooth count that the AOD uses, the balance weight for your 351M is 28oz-in same as 289, 302 before 1985, 351C, 351W and 400. they all use the same weight except 302 when it went to 50oz-in in 1985 IIRC. the 2 you need to work on are the converter stud pattern and the offset. C4 usually uses a 10.5" stud pattern while the FMX, AOD & C6 usually use a larger 11.5" or 11 7/16" pattern. you'll find them listed either way, they are essentially the same. from what little i remember the C4's use a different offset than the FMX, AOD and C6 but some say if everything else is right they'll swap, IDK.

i would go straight to an FMX / AOD 164 tooth flex for a 351C, 351M, 351W or 400 engine for a 99% fit

personally i'd also skip the adapter plate and move to a 351W rather than replant the 351M,

unless you're upgrading it to a 400 internally? the 351W is still correct to the H vin code.

or if you're interested the 351M can be 'corrected' to perform on a decent level, that means over-all efficiency not turning it into a pig ... sorry but they already have that covered. the issue lies in the lack of both static and dynamic compression ratios, barely 8:1 with retarded camshaft timing doesn't cut it, it can be corrected 

don't forget the throttle pressure valve cable kit for the AOD,

the pressure has to be set using a gauge, too little pressure and it'll smoke the trans in 3 minutes

better to have a tad more pressure than a tad less

http://www.monstertransmission.com/Ford-429460-351M400-series-motors-to-Ford-AOD-Adapter-Kit_p_18413.html#.XzCG3jVOncs" rel="nofollow - https://www.monstertransmission.com/Ford-429460-351M400-series-motors-to-Ford-AOD-Adapter-Kit_p_18413.html#.XzCG3jVOncs

same kit for less? Monster probably drop ships from PATC

http://transmissioncenter.net/shop/adapter-to-install-an-aod-overdrive-transmission-on-a-460-big-block-ford-motor/" rel="nofollow - https://transmissioncenter.net/shop/adapter-to-install-an-aod-overdrive-transmission-on-a-460-big-block-ford-motor/

but like i said, for that $ i'd go a different direction, maybe even an FMX engine block

I think I also have a picture of a 400 with that odd looking rear side.

I had an AOD set down into my 73 Ranchero before stopping work on it. The AOD will set fine on one pair of the cross member holes, but if an adapter plate is used, it will need altering. It looked like a C6 driveshaft will be close, my car came with the C6. The C4 uses the other pair of holes, was my guess.

That 85 AOD you have, it isn't a police model is it? The 80's police Crown Vics used a weird shift pattern(VB internals). Those have a manual 2nd gear shift position, and no 1st gear position. The difference in those is inside the VB, one valve chamber in particular. I never changed mine, but considered it when I learned of that. I owned both an 85 and 86 P71 CV, and also bought a spare 351W/AOD to rebuild(that was about 1994).

I agree on the 351W swap, the large block 351M and 400 are less than ideal. I love Cleveland heads, but that weight and low compression sucks.

The AOD can handle some power, but not much in 80's stock form. The "A" OD servo is a must, but I would swap most of the guts from a later 4R70W, including the wider OD band. I have those spare parts unfortunately, I was collecting for a close ratio 4R, and got sent the wide ratio stuff instead.

I just found out that one sun gear shell is super rare(the AODE unique part). I need one of those for sure for my 92 Mark VII, and maybe one later for my work truck if I don't retire first. I'm putting a 347 into my Lincoln, with a 4R that has the AODE planetary etc(four parts). That will make it the same gearing as an AOD, close ratio, and work well with the 347 and stock 3.27 gears. I have an AOD that I built with a new AODE sun gear shell, so I think I'll be taking that apart soon. I also have a 94 Mustang GT(AODE), and might pull that too given how rare that part is.

I am keeping my 351M, not that I'm in love with the motor because there's nothing easy about it, but it's the motor that came with the car, and this is kind of a special car. I got a 400 crank for it and will be boring it out to make it a 408 stroker. Fixing the retarded cam timing and some dome pistons (I'll need the 400 pistons anyway) can bump the compression up. Ford Muscle did a nice article where they made a 468 ft-lb torque and 380 hp 400 for $2000. It no doubt will cost more, but I've been following this plan for mine.

ANYWHO, I need to decide if I want to go through the insane PITA and expense to switch out to an AOD. I drove this thing all over hell with its C4 but it only has 2.75 in the rear, and that really needs to go. However, on my 67 Mustang with 14" tires and 3.55 in the back, it's not fun taching 3000 rpm just to go 60 mph with a C4.

Hemmings has a nice article on the swap in general.

https://www.hemmings.com/stories/article/ford-aod-overdrive-transmission

The AOD has close ratio gears, the 1/2/3 being about the same as a C4 or C6. If you go to the AOD, I suggest upgrading a few things for the torque level, and to help it in 1st and 2nd. The "lower" 1st gear makes the rear diff, easier to choose. You can use a 3.25 or 3.50 gear and it'll take off like almost two steps higher, say a 3.70 to 3.90 etc. The math is easy if you already know what you want with the C4 etc.

The wide ratio gears are fairly easy to come by, from any 4R70W. Those change only the 1st and 2nd gears, leaving 3rd and 4th alone. Four parts swapped change those gear ratios, planetary, ring gear, sun gear, and sun gear shell.

You'd definitely want the wider OD band, and that requires the later sun gear shell and reverse drum(preferably the 98+ mechanical diode reverse drum). Throw in the four clutch intermediate pressure plate, and the guts end up being most of the parts from a 4R trans. You can buy those from eBay often, or many trans parts stores. I even have some spare parts like them.

Most of your cost is the labor to build one, find a shop that you can trust.

with a 408 i'd go with a C6


technically not a stroker, the 400 came with the 4" stroke crank, same block & heads, you're just upgrading from 351M to 400 with a .030" overbore to make 408 and no M because it's a 400

or you could say it's a 351M bored & stroked to 408. then it would be a 408M i guess

but anyway, no ing way a C4 is going to hold up behind a 408 unless you baby it. even then you should have enough low end TQ to hurt it bad and i still worry about the FMX / AOD platform. the low end TQ is why i'm having a hard time jumping on the wide ratio bandwagon. true the LTD II is a sled but the 408 should be able to handle it easily. you can get the low ratio planet set in a C6 too, run even a 2.75 or 3.00 gear and it'll be no slouch coming off the line, then when it's in 3rd / regular D range it'll still be right for the mph

http://broaderperformance.com/product/c6-750hp-transmission-wide-ratio-429-460/" rel="nofollow - https://broaderperformance.com/product/c6-750hp-transmission-wide-ratio-429-460/

another direction is a std ratio C6 and Gear Vendors OD

http://www.gearvendors.com/index.html" rel="nofollow - https://www.gearvendors.com/index.html

big car, big motor, big transmission

Cool, I didn't know the C6 had a different ratio option to buy. That helps a lot, the wide ratios were used to allow higher rear gear numbers to lower rpm's at highway speeds. So even a C6 you could use likely two steps of change of the rear gear ratio. With a 408 it would do fine with I'd say 3.00 or 3.25 gears and the wide ratio, that is to say, great acceleration and maybe feasible rpm's on the highway.

An overdrive gear is great but it takes some work to have it survive a lot of torque. The 4R70W has guts that are able to handle it in stock form, thus the "70" rating in the name. But the lesser transmission like the C4 and AOD, they need some upgrading to handle much above stock or mild engines. The parts are out there, you just have to figure them out etc.

I considered an OD transmission, but too much hassle/money with the bell housing issues to run a AOD with the 351M/400 since it uses the 385 series bell housing. On top of the cost of the bell housing, a high performance AOD build is pricey compared to a old C6.  So I had my C6 rebuild with a Broader kit (std gearing), for a fraction of the cost.  In the long term, I'd like to go to 3.25 gears and a Gear Vendors OD, but that's a big investment.  I think that'd be the ultimate setup for my car, giving it a big more snap off the line and and also lower the cruise RPM, but for now, it's great as is.  

If you can't afford a GV OD or don't want the hassle of trying to adapt an AOD, consider just running a C6.  With a built 408 it will run fine and cruise RPM will be okay with the proper rear gears.

For the AOD idea, also keep in mind the AOD is made for either a carburetor that has the proper AOD TV linkage on it, or the common Fox Mustang throttle bodies. Attaching the TV to another carb is not that simple or easy.

The ideal trans is a 4R70W, and a stand alone controller, but those can be $400 or were a long while ago. I'm working towards an Explorer(late 1997) 302 system, the PCM and wiring harness. That'll run any 302 and 4R70W base, other engines would need a special distributor modification(it's a cam synchronizer in those(DIS)). So I'm debating on a 302 or a 351W based block engine(big price difference). Then the transmission is a straight forward deal, work out the shifter, drive shaft and mounting.

 There's a shop not far from me that does that conversion for the  Mustang guys. I think they sell kits for doing that conversion. They are up in Hudson Florida. Haven't checked it out yet.  

I really seriously would consider that for the C4 in my 67 Mustang, it's just not cool with the 3.55 trak locs in the rear now.

Price is not a whole lot different than rebuilt wide ratio from BF, but I would have to buy the C6 and have it rebuilt ($900 for rebuild), in addition to getting the new tail shaft. The GV set up would probably set me back $1000 more than getting a BF wide ratio transmission.

I do agree with the sentiment, AOD sounds like a non-starter at this point.

Perhaps I'm biased, but I agree 700%. I have a 67 Mustang Coupe, a 69 Mach 1 428 SCJ, but this is my favorite of them all. The sentimentality to it probably helps that, but even in highschool, I loved these cars. 

As a freshman, there was a kid in our school who had an Elite and I loved that car because it reminded me of our LTDII we had when I was a kid. Little did I know in just two years I'd get a chance to buy that very same car back from the guy dad had sold it to about 10 years prior. So I did, and it was my car through highschool and college.

I don't know how the Gear Vendor's shift function works, if that would be enjoyable.

The AOD has a few quirks of its own though. The AOD has a unique lock up feature unlike all others. The lock up is only in 3rd and 4th gear, and it is continuous. There is no lock up in 1st or 2nd gears. It's like two different two speed transmissions, the first gears are like normal torque converter trans gears. Then it has a big rpm drop to 3rd gear(1:1), because of the lock up right then, and it stays locked up in 3rd and through 4th.

That center input shaft is long and small, very weak for any performance use. That shaft engages splines that are welded onto the torque convertor housing. So 3rd/4th gears see exactly engine rpm, the TC is not part of the power flow in those gears.

The aftermarket one piece shaft which replaces both stock shafts, that eliminates lock up completely. Then all four gears work through a normal type TC, multiplication in all gears. That also reduces some fuel mileage on the highway. Most people love that shaft for the performance it gains, and they are fine with the extra rpm in 4th.

My stock 90-92 Mark VII's all had the AOD and 3.27 gears, with 26.5" tires(225/60/16) at 70mph the engine's at 2000rpm.

I would compare the choices more than just looking at costs, for the AOD, GV OD, and 4R70W for example. The shift rpm's for the AOD are not easily altered, stock is in the 4500rpm range. 2nd to 3rd is always lower than 1st to 2nd, by a good 300rpm+ for sure. Getting the AOD to survive power at the 350+ level, often needs some internal improvements not done by rebuild shops. I've seen online pictures and descriptions of most of that, but I would prefer to have to do less of that special modifying. The high dollar performance shops are most surely familiar with all of that, but the prices will be as high as any you've heard of.

The 4R70W can be built easily by any decent local shop, and nothing really special is needed until you get above 450-500hp. Those use a cable shifted linkage, some going into from the rear of the trans. So shifter choice and cable etc, are things to work out.  The controllers for it are now many, you need to source that before going deep in cost for the trans. But in use, the shifting is programmable to whatever you need, and it will be the same all the time. The shift pattern for the AOD and 4R70W are different than older C4/C6 three speeds. The AOD has "1 D N R P", so five positions. The 4R70W has "1 2 D N R P" so an extra position on the shifter.

I've had AOD's in multiple cars, and the 4R70W in three so far. I'm ready to upgrade my keeper Lincoln to a 4R, I hope to get to my Ranchero next year to do that last.

I was more going for lack of complexity in C6 vs AOD or 4R70W.

Broader Performance used to have a wide-ratio C4 as well, I wonder why they stopped making that one.

Along with "lack of complexity" the C6 won't need to have an adapter to bolt up to the big-block trans pattern. 4R70 controllers and wiring were in the neighborhood of $800 a few years ago, add a trans adapter, rebuild costs, driveshaft mods, and maybe flexplate/torque converter costs as well...

Cheaper/simpler to use a 351W, or get a Gearvendors add-on overdrive for the existing trans.

Lizer wrote: Another option is to pick up a $100 C6 off Marketplace, take it to my local rebuilder to rebuild (it was $900 to rebuild my C4, including converter), and get the Broader Performance wide-ratio gear kit for $400 and have them use that.

run that idea by your builder and ask him "What if the C6 core needs hard parts ... are they included in the price or extra? IMO going with the Broader complete transmission would be a bargain considering the total package including experience putting that package together. don't get me wrong i like to support my local guys but there's no telling what you'll get inside a core and all the little nifties that Broader does will be ups & extras

I agree, I had the pricing of the 1200hp C6 in my head. At $1700 for the wide ratio package, I don't think the local shop can do it for that. It costs about $900 to get a new rebuilt TracLoc chunk from several vendors on Ebay, and they can't do it for that either.

You should want an 87 or newer, and the application is very important. You should avoid older units, a police CV(the shift pattern(2nd, no 1st)), and the plain model versions(low power commuter cars).

They all need help, but some are much better to begin with(the 302 HO cars etc).

The Mark VII's were about the best to begin with, most Lincoln owners would never manually shift their cars. All of those HO version AOD's are virtually identical, the 1987ish range is where the last output shaft improvement was made.

All AOD's need the "A" OD servo, and the AODE/4R70W intermediate pressure plate(it's thinner and allows four clutches instead of three. The early AOD's had only two of those clutches, and most low powered versions had "C" OD servos. Throw away those low end parts, those are what burned up very fast in early 80's AOD's. The police destroyed tons by the OD band burning up, someone must have been able to force WOT and 4th gear, which is stupid for an OD band. I read ages ago of how to do that in the VB, but I'd never consider it.

The guts of the AOD are all the same internal hard parts by name, as any AODE or 4R70W. The hard parts are not inherently weak links, but in above average/stock power, those parts are very important for reliability etc. So upgrading those parts is simple for anyone who builds Ford trannies, given the knowledge and finding the later trans to donate parts from.

Grab any 98+ 302 Explorer trans(4R), and you have almost all of the best parts to stick in an AOD(the rotating guts). They don't all swap over, but what does are all better than what's in all AOD's. The AOD still has to rely on the weird input shaft arrangement, and the rest of the control system(VB and servo's etc). Install the right shift kit, VB parts and upgrades, and it can be very strong. Aftermarket companies do VB's in many ways, full manual stuff mostly, and some automatic versions that just work better than stock.

I liked the TransGo HD VB kit the bet of the many I did in the 90's, it made almost everything way better, especially the driveability. The trans would downshift far sooner than any other VB kit, at throttle amounts below WOT. Getting onto a highway on ramp at a low or medium speed, the trans effortlessly went down a gear or two as needed. Basically it very quickly went to the lowest gear possible that you would want if performance was the goal(think road course instead of fuel mileage).

That's the AOD I rebuilt last, with the AODE wide OD band parts in it and Kolene steels, thin frictions in the direct. Years later we find out thinner frictions and steels is generally a bad idea. So I will be R&Ring that AOD to change the guts some. I need the sun gear shell from it to build my Lincoln's 4R70W(again I want the close ratios(requires that rare AODE sun gear shell(obsolete))). I had that before rebuilding it, shifting at 5400-5600rpm, 2nd/3rd was again lower(maybe 5000).

That difference between the first two gear shifts is very hard to fix(even out). I've read this past Spring of how the 2nd/3rd shift can be raised, that would be a huge improvement assuming it works.

The AOD needs a bunch of special building processes done to increase reliability above mild power, few place know of them or have done it. I've read of all of that, but most didn't exist before 2000 when I built that last AOD. So if you want an AOD, research carefully about the myriad of possible upgrades available, from parts to building steps. None of that is basically available at any local shop, but every shop could do it all if they knew what to do.

Don do you have a preference for Blue Plate kevlar or Alto Red frictions?

or is there something else that's come out since then?

I recall those being about the best to use 20 years ago. I have blue clutches for all frictions of the AOD I mentioned, and Kolene steels(the black coating) in it too. From what I've heard in the last ten years, the OEM kind of Borg Warner frictions are as good as anything else. Smooth frictions are to be avoided, they make it hard for ATF to displace, so some slipping is assumed with those kind. I think the Kolene steels are still good, but not really any advantage as thought before.

What gains the most in power capacity is increasing clutch pairs without going to thinner frictions or steels. Sonnax now makes two new drums, in two versions of each. The best of the pairs adds one clutch set, for the direct drum and for the forward drum. That special direct drum is for 4R's and AODE only, I don't think it can be used in an AOD. The forward drum is under $200 and worth it for big power.

The direct drum is a kit that comes with a special sun gear, and is made with the stub shaft built onto it(which in an AOD is where the small input shaft engages the direct drum). So an AOD with that couldn't use the lock up shaft at all, only the one piece aftermarket shaft might be possible to use it in the AOD. That direct drum kit is about $600 or just under.

So add a clutch pair to the intermediate(2nd gear), one to the forward drum, the 98+ reverse drum, the wider OD band parts, and the several rebuild tricks for an AOD, and they can easily handle 500+hp. The high end builders know all of this stuff, they undoubtedly collect spare used AODE/4R70W's for the guts to put into AOD's.

Anyone can buy those in the same way, and find a builder to put it all together. The hard part is finding the tricks to do i the build process, and have your builder do all of that. The 4R70W doesn't need much at all beyond the stock rebuilding process.

That's how I can build my own 4R's that I have planned near future, they don't need much besides good rebuild parts. I own those special Sonnax drums, I have bought them to build two 4R's soon. The first will be for my Lincoln, using the AODE gear set(gives me the same close ratios as the AOD). I do plan to take some pictures to post on the Mark VII forum, though they have nobody really in need of such a transmission. Nobody hot rods a Lincoln really, not many anyway. It's a fun hobby.

Here are the two high capacity drums from Sonnax, the forward drum drops into any AOD/AODE/4R70. But the direct drum I don't think can go into an AOD, but it's cool to look at.

https://www.sonnax.com/parts/4373-smart-tech-high-capacity-forward-clutch-drum-kit" rel="nofollow - https://www.sonnax.com/parts/4373-smart-tech-high-capacity-forward-clutch-drum-kit

https://www.sonnax.com/parts/5057-smart-tech-direct-clutch-drum-shaft-kit" rel="nofollow - https://www.sonnax.com/parts/5057-smart-tech-direct-clutch-drum-shaft-kit

AOD has the mechanical lockup in 3rd and OD with the stupid hollow split input shaft in the trans.

Those break with abuse, (especially in heavier cars or trucks). AOD also has the hated TV rod or cable to be an added pain in the setup. AODE, 4R70, and 4R75 are progressively stronger derivatives/descendants with electronic lockup and computer control. In a perfect world, the 4R75 would be the choice.