I’m looking to swap the trans in my 70 cougar and need some help. I will be installing 3.73 gears as well with my 351C. I plan on street driving the car but also plan on taking it to the drag strip to race as well. Should I go with a built c4 or do an Aod transmission for the car? Any help would be appreciated.
If you are going to be drag racing much, and want the O-drive, get one from a late model Mustang.
You might also want to consider a C6 if you want to keep it looking more original but handle some higher HP. I’m surprised your 351C doesn’t have at least an FMX or even a C6 already vs. a C4. Not that the C4 is a bad option, just each step is designed to handle progressively more HP and I would think the C6 should be just as easy to find built…
Just another opinion…
Do the AOD swap - you won’t regret it if you plan on spending any time on the highway with those gears. I had a 69 street/strip with 351W, 4.11s and AOD. It ran 13.20s at 103 but could cruise the highway at 70 mph at about 2500, IIRC. Best of both worlds.
I’m currently in the market for another Cougar, and I will probably build a little less motor, but will still likely have 3.55s or 3.73s and will definitely have an AOD again. Just make sure you get an AOD, not an AOD-E (electronic overdrive).
Some 351C in F series trucks came with a C4,
these had stronger casing and tougher internals,
I had one behind a 351W mustang 430hp/410 touques,
it was beaten for many years at the drag strip in my younger days.
never gave a problem.
A few years ago there was an article in Muscle Machines about a guy who built a C4 that handled 700HP. I still want one.
This is not even a hard call on any front …let me help yoiu
You used two important words
Drag & Strip …
This means the choice by a 1/4 mile is the C‐4
C-6 eats too much power…the AOD will fail unless you put the cost of 3 C-4"s into it
Go to any strip and ask the guys driving fast Fords
If they are not running a ]power glide
They are running a C-4
I can’t get over the fact a C6=60 HP right out the tailpipe… I really never cared for that trans personally.
I am swapping out my C4 to an AOD. Does anyone know what length the Drive Shaft needs be? If anyone knows the length I need or a link where I can purchase one that would fit it would be greatly appreciated. My engine is a 289 gears are 3.55 suspension is stock.
I put a AOD in my 67 and used the stock driveshaft with AOD yoke with one inch cut off the yoke snout.
Do you have a link to the yoke you purchased?
Would you happen to have a part number or link?
Sorry, just read the last post, I removed the snout from a 80 something T-Bird D/S.Which the whole trans came out of.
This might help! www.bing.com/search?q=aod+transmission+slip+yoke&qs=SC&pq=aod+trainsmission+slip&sk=SC1&sc=5-22&cvid=46693B7997B14C178105FDD38767B90E&FORM=QBLH&sp=2
Thank you!
Don’t go with stock steel driveshafts, if you have a choice on any overdrive transmission (assuming you put in proper rear gears to take advantage). At best, you’ll be wondering why you have a noisy thrumming sound as you’re tooting along at 80 MPH. At worst, you’ll lunch the rear end pinion, tailshaft, U-joints, or bend the shaft.
Even Mustang guys have problems with this, and with our even-longer Cougar driveshaft, the problem is magnified.
Instead, go with aluminum (stock Explorer driveshafts are often a great choice!) or composite. They resonate at a frequency high enough to probably survive even at Bonneville speeds, and don’t create problems.
The C4 transmission is excellent but a 351C would probably destroy it. AOD unlts can be beefed up for supercharged later model engines & would probably work great with a 351C. They have been used with supercharged stroker 5.0 engines. The C4 is best used with mildly built 289 or 302 2bbl or 4 bbl engines. Of course, you can beef up anything.
My last Cougar was a 1970 ex-race car. Racing caused the passenger’s side subframe rail to start peeling off the subframe. Basically racing destroyed the vehicle & I ran out of money restoring it. My current 1968 has an excellent straight body & I plan to gently drive it. These cars aren’t full framed like Crown Vics or even Torinos. Racing them will, in my opinion, destroy them.
Around 1993 i replaced the fmx in my 73 convertible with an AOD. At that same time rebuilt the 351c with edelbrock cam/manifold/4v and replaced tge 2.75 open rear with 3.25 limited slip. (Got the pumkin at a car show for $100!) Fairly mild, but still much more powerful than the 2v.
It’s run flawlessly since. But only about 2000 miles/yr in wisconsin summers.
The trans was bought used for 200. Rebuilt for 350. Install costs were (est) 200 more. About 750 all in. Since them the increased fuel economy from 11mpg to 18mpg has saved 1700 GALLONS of fuel. Wasn’t done as a cost savings, but it has saved.
Unless you need / want originality OR are a drag racer, there is no negative to the AOD swap.
Has anyone put a 4R7W transmission in a 69 car and if so who’s cross member did you use .
You can often use the stock crossmember just by drilling a couple more holes, but they sell them on Summit and other sites for around $150.
AOD and 4R70W mounts are interchangeable. The only real difference between your stock mount, and one for this transmission is likely to be that the bolt holes are a little farther back.