Overdrive Transmission for 630 HP motor

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davidcribbs

davidcribbs

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I went through the current threads, and couldn't find what I was looking for, so I wanted to post my question. This isn't actually for my '67 GT Convertible, but for my '55 Pilothouse Truck, although the info should be mostly the same. I am building a 630 HP 383 > 496 that I am putting in the '55 truck. It will be mainly used driving around town, and I would like to mate an overdrive tranny to the motor. My truck currently has a 4 speed in it, but I don't care whether after the rebuild it stays a manual transmission or automatic. My two goals for the tranny are its ability to handle 630 HP, and have overdrive capabilities so it is more streetable. I know that there are some after-market options with Tremec, and the like. I would like to see if anyone has used a high HP motor, and had a Mopar transmission that has handled the HP and been good on the highway. I would probably be remiss if I didn't mention that I do not want to cut the tunnel in the truck too much, since the cab of the truck doesn't have a crap-load of room to start with. Thanks with any information you can give.
 
For something that light, "why?" Just use a 4 speed and a street gear like 3.54/3.55 just like we did back then. Something with that oomph cal pull a higher gear
 
67Dart273 said:
For something that light, "why?" Just use a 4 speed and a street gear like 3.54/3.55 just like we did back then. Something with that oomph cal pull a higher gear
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You are correct, I just know driving around with my wife, it will make it a much nicer drive to have the overdrive :)!
 
There are a few companies that will build you a 4L60 or 4L80 for you with a custom bell to match your engine.
They handle LS engines no troubles.

Try look that up.
Hope this helps.
 
I have a 86 dodge d150, 318 with a 727 electric overdrive. I have heard these transmissions have all the durability of a regular 727. Might make a good choice after beefing it up to handle your torque and horsepower.
 
ch1ll said:
I have a 86 dodge d150, 318 with a 727 electric overdrive. I have heard these transmissions have all the durability of a regular 727. Might make a good choice after beefing it up to handle your torque and horsepower.
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They lived, at least for awhile, behind V10 pickups and Cummins
 
On that same topic - anyone have a 518 running higher than stock HP through it?

The 90-95 ones seem to be getting less common.
 
I will be . I have a built 46rh on my bench that will probably handle 650 hp . They build them for built cummins ….
 
Syleng1 said:
There are a few companies that will build you a 4L60 or 4L80 for you with a custom bell to match your engine.
They handle LS engines no troubles.

Try look that up.
Hope this helps.
Click to expand...
My buddy has a trans shop, most of his business comes from rebuilding the 4L60 / 4L80's, they are not bullet-proof and have issues.
 
Syleng1 said:
There are a few companies that will build you a 4L60 or 4L80 for you with a custom bell to match your engine.
They handle LS engines no troubles.

Try look that up.
Hope this helps.
Click to expand...
i think that would fit the bill nicely for what he's trying to do.

a 2004R could probably be spec'd out to take the abuse with the bonus that it's a relatively small package comparison wise.
 
I think I read somewhere back in post #1 that he was looking for a Mopar transmission .
Plenty of Mopar stuff that can handle it.

Back in the 60’s,,,,,Dick Landy was driving an altered wheel base car for Mopar .
It had a nitro Hemi in it,,,,and a 727 !
It Worked behind about 1500 HP at the time !

Yes,,,he blew a few transmissions too,,,but only after several runs .
A good 727 can easily hold up to 800 hp or more,,, with some good aftermarket parts.
And this Ops car is not going to be on a sticky drag strip with slicks,,,,behind Nitro !

I agree with the guy earlier ,,,call Cope !
You don’t need an overdrive unit,,,,,just a good rear ,,with a decent gear .

Tommy
 
Desoto291hemi said:
I think I read somewhere back in post #1 that he was looking for a Mopar transmission .
Plenty of Mopar stuff that can handle it.
Click to expand...
yes, and overdrive

sooo... a 518 or 46RH with probably *checks notes* a JW ultrabell... and all the associated upgrades.

i know that around here, 518's and 46RH's are hen's teeth. so once you've factored in the price to obtain a core and then the price of repair components, upgrades and a rebuild (if you can't do that yourself), plus a full custom converter... you're easily into the 4L/2004R territory that enjoys much much broader parts availability and aftermarket support.
 
67Dart273 said:
For something that light, "why?" Just use a 4 speed and a street gear like 3.54/3.55 just like we did back then. Something with that oomph cal pull a higher gear
Click to expand...
True … if it is for a driver 650 hp and corresponding torque even 3.23s would work .
 
My 70 Charger weighing 4000lbs pulled 12.30s with 3.55s and a 9:1 440 / mild roller / MP template ported 906s and headers. 3.23s and a 727 would work fine. And I imagine you have 28” + tires .
 
Kendog 170 said:
Have you considered a gear vendor OD with your 4 speed? May not have to cut anything in your truck.
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I have been looking at that as well, although I am a little Leary about adding another possible breaking point on the drive train. Has any else used or have knowledge on the reliability in real world applications?
 
ch1ll said:
I have a 86 dodge d150, 318 with a 727 electric overdrive. I have heard these transmissions have all the durability of a regular 727. Might make a good choice after beefing it up to handle your torque and horsepower.
Click to expand...
I had not heard of this before, but will look into it. Thank you.
 
The diesel guys have been running the 46RH/47RH/48RE behind high horsepower/high torque diesels for years. With the aftermarket hard parts that are available to replace the weaker parts OEM ones yours has in it, there is no reason to look at other OD transmissions. Do a google search for those companies that modify those transmissions and see what they might have to offer you. One company I recall dealing selling those parts to was called Farm Boy Diesel.
 
I've been running an Extreme Automatics Stage 2 - 2004R transmission with a 3800rpm stall converter with 3-carbon fiber lock-up clutches in my 408 Magnum powered '68 Barracuda convertible for nearly a decade now. It's the best performing transmission I've ever had the pleasure of owning. It's compact, very strong when built properly and the gear ratios are nearly perfect. I run 3.91 gears with 28" tall 275/65R15's.

I'm essentially doubling the horsepower with my latest upgrade, and am installing a Stage 2 - 4L60E from Performabuilt rated at 900hp. I also had the super-low ratio 1st gear changed to a ratio much closer to the 2004R with a 6 pinion gearset.

The 4L60E fits in the car with only a minor modification to my custom crossmember, as the mount itself is in a slightly different place. I did not have to cut the floor to install the 2004R, but I did modify the torsion bar crossover to fit the transmission in the tunnel with the proper driveline and pinion angles.

The 4L60E is fully programmable, which is a nice feature, but this transmission is as yet untested in my case.

Note the fully spot welded seams, which I did while installing the full US Cartool Chassis Stiffening Kit. I also added my own version of a Monte Carlo Bar to help support the front half of the car.

I was blessed to have found such a rust free example of this A-Body. The chassis was very strong even before adding the US Cartool kit.

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20241004_113221.jpg


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