Which transmission?

[PeteyDaMan]

Hi all,
I'm getting ready to put my new 512 in the car but I'm stuck on which transmission to use.
the car is originally an automatic but I really want to get a manual in so I'll need a conversion kit.
The 2 kits I'm looking at are Brewers kit with an 883 or Silver Sports kit with a TKO 500. I don't want to try and source the parts myself as I'd like to get this installed in the next few months.
The 512 should put out somewhere between 550HP and 600HP. The tires and suspension will be the limiting factor in putting the power to the pavement. I'm welding in sub-frame connectors, torque boxes and adding a set of Caltrax bars. the rear end is an 8 3/4 with a 489 case, suregrip and new Richmond 3:55 gears. The car also has all new suspension bushings and springs.
The car will not see the track. It's a car night cruiser and street pounder.
Any advice is greatly appreciated

 

[PRND21]

If you go with the Tremec, you’ll want a TKO600. I don’t think a 500 would handle the torque. I’ve got a 600 in my Belvedere. The Brewer’s setup will be easier to install.

 

[WileERobby]

What is the cost & installation difference between the two choices ?

 

[PeteyDaMan]

The installation is about the same with each, maybe a little more complicated with the Tremec due to the hydraulic clutch cylinders.
Cost, the 833 kit is about $1000 cheaper but that's not a real driving factor in my decision.

 

[5.7 hemi]

You WILL be cutting the floor for the Tremec, but double od will be nice on the freeway.

 

[rebel513r]

I would go t56 magnum

 

[moparmarks]

The 833 is a simple install
The TKO will require more work. Tunnel will need to be modified in order to get the tranny high enough to maintain proper pinion angle.
The T56 will require a new tunnel. Really fat tranny.

833 is bullet proof and shifts great.
TKO shifts like crap.
T56 is strong and shifts great.

 

[PRND21]

If I were to do it over again, I’d be looking real close at Passon’s 5 speed.

 

[moparmarks]

If I were to do it over again, I’d be looking real close at Passon’s 5 speed.

Just did one in a 70 Challenger R/T with a 440. We just love it. Getting one for the Dart next.

 

[PeteyDaMan]

The Passon 855 would add $3k to my build putting it out of reach for me.
I've heard of high rpm shifting issues with the TKO which concerns me
If I was to go with the 833, I'm guessing I should probably go for the 18 spline or would a 23 spline be ok?

thanks for everyone's input

 

[moparmarks]

The TKO setup is not much less than the 855 and a lot more work. I've done several TKO's. Won't do another one on any of my cars. Another thing I don't like about the TKO is that the setup uses a Ford tranny. The Mopar shifter sits clear off the back of the tail housing requiring the drive shaft yoke to be moved out further to clear the shifter.

 

[moparmarks]

Do the 18 spline for the 833.

 

[vintage chromoly]

Stop overthinking it.
Get a nice 18 spline 833 and call it a day.

 

[biomedtechguy]

If you go w/a 833, 18 spline is the only choice for a once and done.
My 855 is AWESOME and shifts-under power-with a quick tap on the clutch pedal, gas pedal stays on the floor and shifts like a hot knife through butter. SOLID is the best way to describe it. Not "precise" meaning it doesn't have a short throw "snick-snick" sterile surgical feel, but not sloppy, at all, just an industrial strength beat the crap out of it over and over and NEVER miss a gear or break anything.
IT IS A BEAST and a beautiful, outstanding masterpiece of engineering and DEDICATION to US and all the MOPAR nation!
Jamie Passon 855 5 speed

 

[HEMI-ITIS]

I will NEVER give up my pushbuttons,,,,,,,,,,,,,,,,in this car!

 

[m79ded]

I would like to do an overdrive for my 79Magnum but in a Automatic form, would make cruising much easier.

 

[moparmarks]

I would like to do an overdrive for my 79Magnum but in a Automatic form, would make cruising much easier.

An early TF518 works great. Did one in a 70 Cuda vert 340.

 

[69sunfireGTX]

TKO shifts like crap.

I've heard of high rpm shifting issues with the TKO which concerns me.

Unless you plan on shifting above 6000rpm you should not have any problems shifting the TKO 600

The T56 Magnum is much better at high rpm but will also cost you about a grand more than the TKO 600. The TKO 500 is cheaper than the 600, but doesn't have the torque rating that the 600 has.

 

[andyf]

Pretty complicated question and you're asking the question a little late in the process. You already have 3.55 gears in the rear which basically says you need to go with the four speed unless you're willing to redo the rear gears again. You would want steeper gears than that to work with a 5 or 6 speed transmission. Looks to me like your best option is a four speed. I don't think the TKO is a great transmission for your application and the T56 is going to be a major investment. The 855 might be a good choice but I think there is still a waiting list for those. Plus you would probably want 3.90 or 4.10 gears to make it really work correctly with your engine.

 

[biomedtechguy]

The 855 might be a good choice but I think there is still a waiting list for those. Plus you would probably want 3.90 or 4.10 gears to make it really work correctly with your engine.

I stepped up from a 3.54 to a 4.10 and run 2,750 at 70 in 5th w/the 4.10 vs 3,500 at 70 in 4th with the 3.54!! Best of both worlds!
I would be surprised if Passon has cleared his waiting list, he had a few hundred people waiting. Although I am beyond happy with my 855, I may have considered a T-56, but that would require surgery on the car, and there's NOTHING that I don't like about the 855. It has some gear noise, but as loud and boisterous as my car is that doesn't matter. The 855 is rated for at least 700 continuous ft lbs of torque!
Now if I had a 440+6 or 426 Hemi Superbird, or another numbers matching or 100% pristine car-then the ONLY aftermarket 5 speed manual is the 855 because it requires NO CUTTING.