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Upgrade Torque Converter with Gears?


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Well title pretty much speaks for itself, I am finally making the change from highway 2.73 gears to an Eaton TrueTrac with 3.70 gears in my 9" for some more umph! My car is a '72 Convertible with a mildly built 357c and a FMX. 

 

 

Made 270whp on the dyno with a crappily tuned 650 carby, hoping to be closer to 300 now. Motor Specs if interested:

 

 

Holley Sniper EFI

Bored 30 Over

Powerheads Aussie 2v Closed Chamber

KB 30cc Dished Hyper Pistons

Comp Cams Hydraulic Roller 0.566 in lift, 270 int/exh duration, operational range 1800-5000

Comp Cams Valvetrain Roller rockers etc

Edelbrock Performer Intake

Doug's Headers

 

 

Looking to have a car that I can daily to work, but still reach the 12's at the strip. Do you guys think it is a necessity to get a higher rpm torque/stall converter to go along with the gears? Seems like everyone is at a crossroad concerning this subject, whether they are other forums online or guys I've asked in person.

Thinking a 2500 rpm stall speed, but someone I spoke with said it made their car a pain to drive daily and recommended an 1800...

 

Looking at this one in particular right now:

https://www.summitracing.com/int/parts/hup-38-25

 

What do you guys think? Any help is appreciated, let me know if I forgot to include any info!

 

Thanks,

 

Adam

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You might give the spreadsheet in this thread a try. It also helps you to understand what goes into selecting a torque converter.

https://www.7173mustangs.com/thread-torque-converter-selection?pid=208498#pid208498

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“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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You might give the spreadsheet in this thread a try. It also helps you to understand what goes into selecting a torque converter.

https://www.7173mustangs.com/thread-torque-converter-selection?pid=208498#pid208498

 

Wow thanks for that and the quick response Don! Punched everything in and puts me right at 2400-2600 as expected! 

 

Was more inquiring about people's personal experiences with adding a high stall torque converter and how they liked it in terms of acceleration vs daily drivability, and if anyone had used that Hughes converter before? 

 

Thanks!

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I went from an open stock 3.25 to a tru trac with 3.50 gears. I also have had a recently rebuilt engine and transmission with a transgo shift kit. I have a TCI 2500 stall torque converter and it’s fine driving around town. So I don’t know about the Hughes. I was going to go with the 3.70 rear gears, but glad I didn’t. As it is I turn about 3000 rpms at 65-70 with 15” wheels. I still have plenty of torque at take off, even spins the tires at a 35-40 roll. I have to be careful with it, it really likes to go sideways now. :)  But I’m not taking my car to the strip, so 3.70 gears or more will be great for what you are looking for.

John - 72 Q Code

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Nice to see you back on here @NewAgeMuscle !

Watching once every while a vid of you and mates on your channel.

 

About to order a Hughes myself for my 71. They look nice on specs/way they're made/materials and they are affordable for farAwayPeople like me.

Curious to read some experience on these too, if any bad, before I press the order button...

73 modified Grande 351C. (Finally back on the road woohoo!) 

71 429CJ. ( In progress )

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I am running a 408C backed by a c4 with a B&M holeshot 3,000 stall converter. I don’t take mine to the strip but I drive it in summer as much as possible usually couple days a week to work. I don’t mind the stall converter at all. I am running 3.73 gears and like them a lot around town but on long road trips it’s a bit of a pain. Around 2800-3000 rpm at 65 mph. I will be installing an overdrive in the future, just haven’t got that far yet. I would also check and see what converter your cam recommends. But I don’t think 2600-2800 will hurt you one bit.

Kevin
1971 Mach 1

408C Stroker - C4 w/3,000 stall - 8.8" Rear w/3.73's - Disc brakes all way around.

 

 

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I'm running a 408C C4 3.5 9 inch Trutrac with a Hughes 3000 stall and more than happy with it

Some have said the Hughes tends to be a little loose stalling higher but didn't experience this

Normal driving is no problem but once you step on the loud pedal things become fun!

Like Jpaz says it likes to get a bit sideways even when rolling at 30-40 mph

Definitely with your combo around 2500 rpm you won't regret it

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I went from an open stock 3.25 to a tru trac with 3.50 gears. I also have had a recently rebuilt engine and transmission with a transgo shift kit. I have a TCI 2500 stall torque converter and it’s fine driving around town. So I don’t know about the Hughes. I was going to go with the 3.70 rear gears, but glad I didn’t. As it is I turn about 3000 rpms at 65-70 with 15” wheels. I still have plenty of torque at take off, even spins the tires at a 35-40 roll. I have to be careful with it, it really likes to go sideways now. :)  But I’m not taking my car to the strip, so 3.70 gears or more will be great for what you are looking for.

 

Glad to hear the 2500 is good, what trans do you have? Also what size are your tires? I'm also on a 15" but I have 275/60s so 28" tall, hoping it won't be too annoying on the highway.

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Nice to see you back on here @NewAgeMuscle !

Watching once every while a vid of you and mates on your channel.

 

About to order a Hughes myself for my 71. They look nice on specs/way they're made/materials and they are affordable for farAwayPeople like me.

Curious to read some experience on these too, if any bad, before I press the order button...

 

Fabrice!! Thanks for watching, hopefully I get more videos out soon especially with the new additions of the coronet and el camino :)  Yea after reading the responses to this post sounds like the 2500 Hughes will be a good option. Too many BMWs and Mercedes running around Vancouver, the ol mustang needs all the help it can get to stay competitive  lollerz

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I am running a 408C backed by a c4 with a B&M holeshot 3,000 stall converter. I don’t take mine to the strip but I drive it in summer as much as possible usually couple days a week to work. I don’t mind the stall converter at all. I am running 3.73 gears and like them a lot around town but on long road trips it’s a bit of a pain. Around 2800-3000 rpm at 65 mph. I will be installing an overdrive in the future, just haven’t got that far yet. I would also check and see what converter your cam recommends. But I don’t think 2600-2800 will hurt you one bit.

 

Thank you for the info! How tall are your rear wheels/tires? I'm looking to stroke in the future as well, but for now going to work with what I got for the quickest daily-able setup I can :)  Overdrive would be great, just gotta save some money then pick between the AODe vs a gear vendors unit on a c4

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I'm running a 408C C4 3.5 9 inch Trutrac with a Hughes 3000 stall and more than happy with it

Some have said the Hughes tends to be a little loose stalling higher but didn't experience this

Normal driving is no problem but once you step on the loud pedal things become fun!

Like Jpaz says it likes to get a bit sideways even when rolling at 30-40 mph

Definitely with your combo around 2500 rpm you won't regret it

 

Beautiful. Yea sounds like Hughes has a good reputation, but even more reassuring to hear from someone like you that actually runs one, thanks for the response!

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Another couple things I forgot to mention: 

 

Is our built-in trans cooler enough for a 2500 converter? I've read people saying there is a need for an aftermarket trans cooler if upgrading the converter, but am hoping that is only the case for applications that don't have one stock?

 

Hughes says their 2500 rpm stall is rated for a big block and a small block will be 300-500rpm lower. Given that our 351cs are midway between a big and small block what do you think the stall speed will be? 2200?

 

Also would my stock FMX on my '72 Mustang 351c 2v be a 29 spline or a 32 spline? 10" core or 12" core... too many options I'm bound to order something that doesn't fit hahahaha

 

Thanks again!

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I believe my tire is 28" tall. I will be swapping in a 4r70w trans to get my overdrive. I do not run an aftermarket cooler on mine. I have had the same little c4 with Broader valve body, b&M 3000 stall converter, stock radiator and cooling lines for over 10 years with multiple motor configurations and have had 0 issues so far. Its been living behind a 600hp 408C cleveland for the last 4-5 years. Im sure if i actually hooked up, there would be carnage. But so far its been good. My torque converter claims to be a 3000 stall but i think its more around 2700-2800.

Kevin
1971 Mach 1

408C Stroker - C4 w/3,000 stall - 8.8" Rear w/3.73's - Disc brakes all way around.

 

 

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I went from an open stock 3.25 to a tru trac with 3.50 gears. I also have had a recently rebuilt engine and transmission with a transgo shift kit. I have a TCI 2500 stall torque converter and it’s fine driving around town. So I don’t know about the Hughes. I was going to go with the 3.70 rear gears, but glad I didn’t. As it is I turn about 3000 rpms at 65-70 with 15” wheels. I still have plenty of torque at take off, even spins the tires at a 35-40 roll. I have to be careful with it, it really likes to go sideways now. :)  But I’m not taking my car to the strip, so 3.70 gears or more will be great for what you are looking for.

 

Glad to hear the 2500 is good, what trans do you have? Also what size are your tires? I'm also on a 15" but I have 275/60s so 28" tall, hoping it won't be too annoying on the highway.

I have a c6 trans with a Transgo shift kit and a TCI Streetfighter 2500 stall converter. Tires are BFG P235 60R 15 so I think they are only 26” tall. You’ll probably be around the same rpm range as me then with 28” tall tires.

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John - 72 Q Code

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What I did was add a 9 quart aluminum transmission pan. I have the stock set up for radiator and trans cooling. No overheating of any kind. I even had it at the Dream Cruise and it was a 90 degrees that day. Stop and go for miles with no problems.

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John - 72 Q Code

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Your FMX would be a 29 spline input and I believe a 12", someone else might want to verify the diameter.

73 Grande H Code. Headman long tube headers, T-5 Transmission, 3.70 Traclok, Lowered 1" all around, Aussie 2v heads w/ 2.19 intake, 1.71 exhaust, screw in studs, full roller cam 608/612 lift 280/281 duration LSA 112, Quick Fuel 750 CFM double pumper, AirGap intake.

 

- Jason

 

 

082-hot-rod-power-tour-2017-1970-1970s.jpg

 

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The cooling capacity of the built in transmission cooler depends on the coolant temperature of the radiator. If you have engine overheating problems the transmission is more likely to overheat.

 

The actual stall speed of the torque converter depends on engine torque at the RPM leading up to the stall speed, which is why there is the differentiation between small blocks and big blocks. Because of the increased torque (stroke) of a stroked 351C it will stall higher than a non-stroked engine, even if they have the same cam, compression ratio, etc.

 

 

“If you can't explain it simply, you don't understand it well enough.”

--Albert Einstein

 

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I believe my tire is 28" tall.  I will be swapping in a 4r70w trans to get my overdrive.  I do not run an aftermarket cooler on mine. I have had the same little c4 with Broader valve body, b&M 3000 stall converter, stock radiator and cooling lines for over 10 years with multiple motor configurations and have had 0 issues so far.  Its been living behind a 600hp 408C cleveland for the last 4-5 years.  Im sure if i actually hooked up, there would be carnage. But so far its been good.  My torque converter claims to be a 3000 stall but i think its more around 2700-2800.

 

Gotcha mine are too. Yes 4r70w seems the way to go, hopefully I will in the future as well. Glad to hear your stock setup has been good, I will keep mine!

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Your FMX would be a 29 spline input and I believe a 12", someone else might want to verify the diameter.

 

Okay awesome to know it's 29, yea hopefully someone knows for sure whether 10 or 12". Would like to do the converter over a weekend, so going to have to order the converter before actually taking my old one out! The Hughes converter says it's 12.75in diameter so I hope mine is too  ::thumb::

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The cooling capacity of the built in transmission cooler depends on the coolant temperature of the radiator. If you have engine overheating problems the transmission is more likely to overheat.

 

The actual stall speed of the torque converter depends on engine torque at the RPM leading up to the stall speed, which is why there is the differentiation between small blocks and big blocks. Because of the increased torque (stroke) of a stroked 351C it will stall higher than a non-stroked engine, even if they have the same cam, compression ratio, etc.

 

No overheating problems, car happily sits at 185-195 even on the hottest days so hopefully I'll be good!

 

Gotcha, I understand why there is a difference, just hoping the 2500 isn't too mild on my 351c. I would like the stall speed to be 2500, so maybe I should get one rated at 3000 instead? This is assuming the Cleveland is like a regular small block and will flash 300-500rpm less than Hughe's big block rating of 2500 leaving me at 2200-2000rpm...

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