I'm trying to find information regarding an AOD Trans alternative for a 1973, 351 Windsor 5.0L engine. The engine was originally paired with a C6 Trans. The engine and trans are slatted to go into a 1951 F1 Pickup. Looking for alternative AOD transmission advice. Thanks!

 

Hey Jay,
Not sure I understand your question. Are you looking to put an AOD in your truck?

We are running one behind our 351W - just need to get the correct flexplate. Baumann Engineering is a good source for all things AOD.

Ben in Austin
1950 F1

 

Ben,
Thanks for response. I currently have a paired (1973) 351W, 5.0 engine and a C6 trans. My original intention was to put the setup in the 1951 F1 truck I am building. I have already reuilt the entire engine with slight hp modifications. Now I'm thinking a AOD trans would be a better choice for a daily driver. I am not sure what AOD trans would mate up to the 351W I have. The overall goal is to get an automatic trans, with overdrive, that will work with the rebuilt 351W.

 

BTW a 351 is NOT a 5.0, it's a 5.8. The 5.0 is the 302.

 

So what do you have? A 302 aka 5.0L or a 351w aka 5.8L. If it is a 351 are you sure it is a 351w and not a 351c or 351m. I assume it came out of a 1973 pickup but the 351w didn't come in a pickup until 1980.

 

Its difinately a 351W. (1973) I'm assumming the trans bolt pattern is the same as the 302-5.0L. It currently has a 164 tooth flex plate followed by a C6 trans, also 1973 vintage. It is a carburated engine. The top two mounting bolts on the bell housing are 5-1/8" apart. I have no history on what type of vehicle the pair came out of. As I bought the engine/trans for low price from a couple of Stoners hard up for cash. I am also assuming the engine/trans came from a heavier Ford car or F-series truck. Tranny swaps are not my forte, but the AOD trans on this older engine would be a good thing. While selecting an AOD trans, I do know that I need to keep in mind that the engine is carburated, possible linkage corrector plate, flex plate weight (50 oz preferable), modified dip stick tube to clear headers and a few other misc dedails. I'm trying to make a decision on keeping the 351W with swapped newer AOD trans or opting for a little bit more modern engine/trans setup.

 

I think you may be confused on a couple things. A 351W with a C6 would have come from some larger car line in '73. Never offered in trucks then. All 351W's use a 28oz imbalance flexplate. Only post '81 302's used the 50oz. Do not attempt to use a 50oz plate on your engine, it will tear it up in a hurry. A late 80's-early 90's AOD would be what you'll want to look for. They have the best upgrades, but be sure you don't get the later AOD-E electronic version. It's designed to work with the engine management computer.

 

Guys,
Thanks for the reply(s). The information is helpful. I did some more research and found that I need to focus on a pre-1986 AOD trans not the AOD-E model, as I am using a carburated 351W. I gotta tell you it is a pain sorting through all the internet opinions while trying to find factual info. This is why I joined the FTE site. It has been a great source for fact based knowledge. Thanks again!

 

Actually, in 1973 the 351W with a C6 was used very rarely. The only such combination that I could find was the 1973 Cougar with the floor shift. Most applications of a C6 with a 351 in 1973 were with the 351C/ 351M/ 351CJ which were all Cleveland's. Perhaps NumberDummy can clear it up.

 

I have to ask, since you have stated that you have no information on the history of this motor, how did you determine that it is indeed a 1973 351W?

 

I'm pretty sure the AOD was used till about 91 or so because mine is an 89 model. Yeah definitly get the lokar cable setup for your carb. Your flexplate is a 28oz. I think you can just buy an aftermarket flexplate for your AOD with the correct 28oz balance matching your 351

 

Joe,
On the starter side of the engine block there are a series of numers/letters stamped that indicate block size, year of build and may indicate build location. The C6 trans also has identification markings as well. There are a few accurate websites that provide the decoding legend for sorting out what the identification numbers/letters mean. Also, the 351Windsor block has specific height and has distintive intake manifold and head bolt patterns. There is plenty of info available defining the identification characteristics of 351W, 351C, 351M, etc.

 

Having built more than a few AOD's, I can tell you two things right away. Your C6 does in fact use a 164 tooth 28 oz. flexplate. The AOD also uses a 164 tooth 28 oz. flexplate when used behind a 351W. It is NOT the same plate, however. ABSOLUTELY DO NOT try to use your existing C6 plate with an AOD. The depth of the plate is different and you'll destroy the transmission and possibly the thrust bearing in the engine as soon as you start it up. There is a 164 tooth plate available with a 28 oz. imbalance that is specifically for AOD and C4 applications. That's the one you want.

The second thing is do NOT mess with ANY AOD built before 1989. There were critical lube system and valve body improvements made in '88 and '89. Earlier units will lose their cookies all over the highway in a short time behind a healthy 351.

 

Hey Jay,
Hmmm... Earlier you mention "I need to focus on a pre-1986 AOD trans ".

I'm with BlueOval - that may not be the best path. Prior to '88 AOD's did not have the lube style Output shaft & were prone to failure. There are also 3 different Overdrive Servos available with AOD's - You don't want the "C" size servo as it was prone to slip off under stress. They were on most AOD's prior to '85.

"The "A" servo is the largest overdrive servo available for the AOD transmission. This piece is used only with 1992 and 1993 trucks and the Thunderbird "Super Coupe" supercharged 3.8 Liter V-6. It will provide a 50% increase in band application force over the small "C" servo and 16% over the "B" servo."

At a minimum I'd look for an AOD with at least the "B'' size servo - post '85 V8 Applications, all 351's, & the high output Mustangs & Lincolns. If you are going the salvage yard route look at '92 & '93 trucks or the larger engine Tbirds.

I hope that helps. We went with a Kevlar "B" sized servo in our AOD behind our upgraded 351W. We also added a Baumann Engineering shift kit to smooth out the shift points. If I had extra cash I'd also go with a solid upgraded valve body (Baumann, Silver Fox, etc.) - that dang cable is very sensitive & adjusting it to get the shift points right while keeping the pressure within spec is a painful experience.

Good luck over there. (I'm not a transmission expert just had to learn a lot about AOD's as part of our truck build).

Ben in Austin
1950 F1 (351W/AOD)

 

​​I have finished a 351w swap in my 1987 Bronco with AOD transmission, after doing research I was aware of the flexplate dilemma. With the research I did, I ordered one that was supposed to be specific for 351w and AOD application. The flexplate I ordered was a pioneer FRA-205. However, after installing the motor and running the truck with a full exhaust, the starter sounds pretty rough engaging the flywheel. Also after driving the truck for nearly two weeks I've seemed to have consistently less oil pressure and believe I've lost my main bearings and now my hunch is that it was the incorrect imbalance. Would you have any further info on my issue?