351C has the same bell housing bolt pattern as 289/302 so C4, AOD, 4R70W will fit.

 

Out of those 3 options, what years I can use without major mods? And what was better? The A0D or 4R70W?

 

If you're going to make a lot of power for a 12 second 1/4 mile, you will likely have to go with a custom, high performance automatic with an overdrive. I don't think factory overdrive automatics, like the AOD, will handle that kind of power. Unfortunately, a high performance automatic will break the proverbial bank.

 

Strongest factory transmission that will bolt right up is a specific 4R70W. It only has 4 forward gears. As far as I know you will not find a 5-6 gear transmission that bolts up correctly without major work. It will need some improvements to hold prepped launches reliably.

 

What year should I look for on the 4R70W?

You could also consider a Gearvendors overdrive kit. I've never used one, but you could bolt one up to an FMX and have the overdrive you want. Just another option.

ok. I’ll look into that too

 

I would check out companies offering swap kits for 6R80's.

I know they sell them for behind other vintage ford engines...as well as the necessary trans controller.

It's really a no-brainer to upgrade to a more modern trans especially if the current one needs replaced.

The only thing I am unsure about is trans case size and if tunnel mods are required.

 

I would check out companies offering swap kits for 6R80's.

I know they sell them for behind other vintage ford engines...as well as the necessary trans controller.

It's really a no-brainer to upgrade to a more modern trans especially if the current one needs replaced.

The only thing I am unsure about is trans case size and if tunnel mods are required.

Some truth to this for sure. Older AOD and AODEs are getting harder to find at a bargain price. Sadly it is getting somewhat hard to find local transmission repair shops that can reliably work on older stuff as well especially if you want to strengthen it. It took me awhile to find a local shop that knew about strengthening an AOD/AODE to accept 400hp+. Even then he said was cheaper to just get a 4R70W and buy the controller. I looked at the 6R80, but the adapters were $600, then a decent controller, and the transmission itself. I think the best route is a 4R70W for strength, control, and price. Lots of ways to do it though.

 

You could also consider a Gearvendors overdrive kit. I've never used one, but you could bolt one up to an FMX and have the overdrive you want. Just another option.

 

I had my FMX rebuilt and improved by a local tranny shop , I did some research on this guy. He is an old ford transmission builder and did them for the 1/4 strip guys for years . He got out of the racing work and opened a small shop in our area. He specializes in Ford stuff only . He’s not cheap but he did me right. Mine shift hard and crisp , before he worked on it , breaking the tires loose in second never happened, now it does. I talked to him just last year and he’s retiring . What we are losing , what shame .
Lots of these guys no longer doing this and the new kids on the block haven’t a clue .

 

SilverFox still sells completed AOD/AODE I believe:
Silver Fox Performance Transmission
Pricing: Silver Fox Performance Transmission

I've got a built AOD and he customized my VB to be constant pressure, adjustable RPM shift points and AOD lockout for 1/4 mile runs so it won't shift past 3rd with the push of a button. Great to work with but I haven't done the first start on my engine/ trans yet to report how it works.

 

Just hard to beat 6 gears and more strength of the 6R80 as compared to AOD.

Properly built C6's good 750hp+ are $2500 and up. Then you still need a $500 convertor too.

At the end of the day when I looked at it, it is a $ wash between rebuilding 70yr old transmissions with 3 gears, higher parasitic loss, and non lockup convertor as compared to a lower mileage dropout 6R80, swap kit, and controller.

The benefits of the 6R80 are huge by comparison for the same money.

 

Bowler Transmission has an adapter kit to mount a 6R80 or 10R80 to a SBF. The kit is $1300. Guess you could start there and find a used transmission and controller to go the cheap route.

Ford Small Block to Ford 6R80/Modular transmission adapter kit

Easily adapt a newer Ford 6R80 overdrive automatic to your classic Ford small block engine. Specs: Works with 6R80 transmission from a Modular V8 from a 2011 and newer Ford V8 5.0, 5.4 and 6.2. It will also work with any of the Ford Modular V8 transmissions behind the 4.6, 5.0, 5.4, 6.2 and...

shop.bowlertransmissions.com

Or you could hit up Performance Automatic and get their SBF 6R80 kit for $8600.

Performance Automatic

6R80 Street Smart Systems

www.performanceautomatic.com

None of those options include all the other stuff you're going to have to shell out for, like a transmission crossmember, new driveshaft, probably re-worked exhaust to fit around it. Shifter, figure out a speedometer setup.

 

What is a 2V 4bbl? It can't be both 2 barrel and 4 barrel carb. Either way, you aren't running high 12's with a stock 351C of any factory specification, with any transmission behind it.

There's another thread here recently discussing/debating gear ratios for ideal street usage, but this thread brings up another point: Going too far to try to drop engine RPM too low at cruising speeds. Modern vehicles with these six, eight and ten speed autos have engines with very advanced electronic fuel injection systems, with the ability to advance ignition timing dramatically under low load cruise, variable valve timing and other goodies that make them much better suited to low RPM cruising than most old carbureted engines. Your 351 Cleveland in stock form may not be as happy cruising at 1,500 RPM at freeway speed as something with modern advanced controls. That's not to say it can't be, but my experience with trying to get them that low has been hit or miss. This becomes more true as you up the performance level on a carbureted engine and shift the effective power band upwards, resulting in an engine that is not as happy at low RPM cruise.

In an old Mustang, I see no benefit from going with anything more than a four speed automatic, like the readily available and very good 4R70W transmission. Pick your rearend gears appropriately to work well with the gear ratios in the transmission. I'd probably go up to 3.25s with a 4R70W.

 

What is a 2V 4bbl? It can't be both 2 barrel and 4 barrel carb. Either way, you aren't running high 12's with a stock 351C of any factory specification, with any transmission behind it.

There's another thread here recently discussing/debating gear ratios for ideal street usage, but this thread brings up another point: Going too far to try to drop engine RPM too low at cruising speeds. Modern vehicles with these six, eight and ten speed autos have engines with very advanced electronic fuel injection systems, with the ability to advance ignition timing dramatically under low load cruise, variable valve timing and other goodies that make them much better suited to low RPM cruising than most old carbureted engines. Your 351 Cleveland in stock form may not be as happy cruising at 1,500 RPM at freeway speed as something with modern advanced controls. That's not to say it can't be, but my experience with trying to get them that low has been hit or miss. This becomes more true as you up the performance level on a carbureted engine and shift the effective power band upwards, resulting in an engine that is not as happy at low RPM cruise.

In an old Mustang, I see no benefit from going with anything more than a four speed automatic, like the readily available and very good 4R70W transmission. Pick your rearend gears appropriately to work well with the gear ratios in the transmission. I'd probably go up to 3.25s with a 4R70W.

My 351C has 2V (2 barrel heads) and a 4 Barrel carb. Thanks for your input

 

Jack, how tall are the rear tires you plan to use ? And do you mean to tell us that you have 2V heads and an aftermarket aluminum intake ? Are you willing to do some engine work also ? You may have to choose a different cam. Getting an engine to be happy at 1500 in overdrive is do-able, but takes some thought. I'm thinking a built up AOD will be your simplest choice. LSG

 

They are stock 14” and I’m going to get 15” stock tire height. Yes 2 barrel heads and currently a Performer intake. I just got the car and it does have a mild cam and Ford Roller rockers. After I adjust the 2 noisy valves I was going to do a leak down test to see engine condition. It’s salty in NJ so I can’t take it to a Dyno right now. A lot say put a 4R70W so I don’t know what to do. I’m willing to go with any gear. Just looking for people that have done what I want to do

 

Who sells aftermarket electronic controllers for the 6 speed?
or do you have to get one at the junk yard.

 

For this scenario, a 4R70W and some steeper rear gears and go get your 12’s.