Anyone running a T56 Magnum 6 speed in a 11 second car?

I'm about to pull the trigger on doing something to generate some cash be it a reverse mortgage or selling my body on a street corner! Sick of my car being on the back burner for years due to 'family issues' and now that 'she' is gone, it's past time to get on the stick with it (no pun intended). I'm wanting to keep my junker street legal and cruise at highway speeds but be able to run at least in the 11's and my thinking is it should do that with the 440 I have and the light weight of the car....a 66 Belvedere 2dr post that has had years of working on weight reduction. Got it down to 2950 well before pulling out the /6 with factory AC and have removed a pretty good amount of weigh since.

I've been a stick guy from back into the 70's and well, I'm sick of automatics so please don't try to convince me that autos are better etc etc etc. Already have a buddy that hammers me every time I mention standard transmissions. And when someone asks what auto you're running after a street race through 3 gears and you're running a stick and they don't believe you....well, I'm thinking I ain't half bad rowing gears. Just would like to pick a trans that will shift when the stick is yanked. I know the clutch is important too and want to make sure that'll be matched also.

I have an 833 hanging around the shop but not too sure I care to rebuild it and go with a GV unit and would like to have something better than a .078 with a 4.30 or 4.56 gears for highway running. Haven't done the math but thinking a 4.30 rear would mean something like a 3.30 final drive? Would rather have something in the vicinity of a 2.76 final. The .60 or there abouts of the Magnum sounds pretty cool to me......

A few points to touch on
not trying to rain on the parade, or piss in your Cheerios
just food for thought more so

the close-ratio 5 speed TK has like a .68 overdrive
there was a thread about it on here somewhere (GD forum I believe)
cheaper than a TK 6 speed
IIRC 6 speed has a bigger case/main-body
the 5 speed has a smaller case too, may fit easier
may have to modify the tunnel
neither is cheap to do

even if buying used take out stuff, it ain't cheap
but you may find a storming deal somewhere

unless you have your mind, set on a 6 speed

you also can get many different
1st (or others) gears ratios (in either a 5 or 6 speed)
so you don't need the 4.30:1-4.56:1 rear gears
1st gear will be nearly worthless,
the gear or torque multiplication will promote too much wheel-speed
you'll have traction issues too,
I think you'll be redlining in far less than 60ft
unfortunately;

you'll also need
10-second & 600+ ft-lb tq 727tf cars 1/4 mile horsepower
to get a standard trans in the mid 11's
especially without breakage

I can slam gears with the best of them too
I just know my limitations & reality, when going fast/quickly

I'm not trying to convince you to not do it
I say go for it

I've had several 11-second manual cars, they break
if you run them like a 'real racecars' is/are ran &
unless you have enough power (like a low/mid 10 second cars)
to walk it out & then get on it, or it will break

even in a lighter 3000# car, not if it's when it will break
been there done that

I'm sure you also know much of your ET
is made in the 60ft & 330ft range, not as easy with a clutch
without breakages, especially if you baby it, have to walk it out
to get it to hook or not to break it

I'm sure you already know
you'll need really good adj. shocks, really good traction,
really good driveshaft
not some old cheap **** that's been laying around
need a quality piece, with nearly indestructible u-joints
& a really good clutch/pref. adj.
& a really good flywheel, billet Alum or steel, not some stock deal
& sfi appr. scatter-sheild if you ever intend on going to a track
& really good sfi appr. driveshaft safety loop
let alone making it work right
then there's the shock-load of dumping a clutch,
even with a clutch-master, softening it on a timer
& all the breakage considerations

get some tires/slicks drag radials with some sidewall
not the low profile nonsense

I'm not what I once was, but think I'm as good as I used to be
sort of sounds like a Toby Keith song

Sorry Cranky I had to do it

Good luck

Go for it...
take lots of video & photos
so we all can see the carnage

Do you have your heart set on a 6 speed? Unless you plan on accelerating in the 130-170 mph range, I find 5th gear in 6 speeds pretty worthless.

I've installed a TKO600 that I pulled out of my old turbocharged Mustang before I sold it, bought a Quicktime bell from Summit, and all clutch components and actuation from Silver Sport to finish it off. This trans survived quite a few street miles of thrashing and 10.90s at 130s easing the clutch out to stellar 1.90 60 foots because I was running stock axles and didn't want to destroy parts...because it was a street car. This was at approx 3700 lbs. 550 hp/600 tq at the wheels.
The 2.87 first gear in the TKO (I believe the new 'X' uses the same ratios, have not looked) vs the 2.66 in the 833 will make the 3.73 I intend to run 'feel' like an 833 paired w/ a 4.10. The .64 OD x 3.73 is equivalent to a non-OD trans paired w/ a 2.40ish rear gear. Intend to run a 28" tire for the time being. The math comes out to 2000 rpm at 70 mph.

Only problem I have w/ the 600 is it doesn't like to shift at 6500 plus. The TKX supposedly has fixed this.

You might play w/ this a bit...
Gear Ratio Calculator (tremec.com)

I am running a passon 4 speed hemi overdrive right now with 4.30 gears and 28" tires.
1st =2.66
2nd = 1.59
3rd = 1.0
4th = .80

The price difference between the passon and the t56 are or were near the same. I believe the t56's only extra cost was in the small parts. I did the calculation 4 or 5 years ago.

I am currently running a 340 stroker (418) with w5 heads.

Now my brain went crazy and i want to pull the 340 out and put the 340 and 4 speed into a 96 dakota.
I want to stuff a big block stroker (512 low deck) into the dart. I have a tr6060 from a challenger that i want to mate to the 400 block. I have a dana with 5.12 gears.

Covid has everything on hold so i cant get my transmission home :-(

I like my 18 spline hemi 4 speed and Hurst Super Shifter

One thing I'll add, having a 4.10 geared tko car with a 440 with a 484 cam - loping along the highway at low rpm and bigger duration cam doesn't actually yield good mpg. Final drive rpms still need to be reasonable for your cam.
4.56's would be just fine, but you'll have so much tq multiplication you'd be launching in 2nd at the track, if not 3rd.

I have a 3875lb car with a TKO600 with the .64 OD., 3.08 diff and runs on 28" 345/40 drag radials. It is a street car. I do drive it to and from the track on occasions. Its not a Mopar, so I don't know if I am allowed to say what it is without getting an *** reaming. I have no roll bar in it so lets say it is an 11.50 car. The lowest 60ft that I have pushed it to was a 1.58 60ft.
I changed the rear diff to a 3.73 recently and I blew the rear half shaft out of it on its first trip out. The tires broke loose, I pedaled it and it went bang. I have not been back to the track since I repaired it. Hopefully I can make it back there this year.
If I could do it over I would pick the Tremec 6 speed over the TKO600. The Tremec 6 speeds are tougher than the TKO600 and shift a lot better at higher RPM's. I admit that my car is an awesome highway cruiser in OD.
Oh, I do beat the crap out of this car on and off the street and it continues to take it. After all that's why I built it.

I would just question, what would the advantage of a 5th or 6th gear be in a 1/4 mile ?

WileERobby said:

I would just question, what would the advantage of a 5th or 6th gear be in a 1/4 mile ?

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none, but OP wants to drive it down the road at speed.

furious70 said:

none, but OP wants to drive it down the road at speed.

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That's what happens when you don't read everything. I can only count to 4, anyway.

Budnicks said:

with a clutch-master, softening it on a timer

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I suggest you look at the Clutch Tamer.
That and a dual disc McLeod setup.
Talk with McLeod about the dual disc clutch they would recommend. I stepped up to the RXT because they recommended it, not for the "1000 HP" power handling capabilities but because it has ceramic metallic discs to hold up to the heat and friction of a properly slipped clutch on a launch that may keep those "slushbox" guys at bay...

Have even thought about running a GV OD. They seem to be pretty tough and might be an easier install.

WileERobby said:

I would just question, what would the advantage of a 5th or 6th gear be in a 1/4 mile ?

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Yup, don't care to buzz the engine all that much when on the freeway....and would probably not use 5th but a buddy of mine did. Can't remember what trans he had in it but he could run 1/8 mile or the 1/4.

5th gear was a "game changer" for me in 2 ways:
Although I only had a 750 RPM reduction in top gear, at 72 mph, 2,750 vs 3,500, it makes a huge difference in noise and my mental comfort level
AND
That was also going from a 3.54 R&P to a 4.10, which is a hoot in 1st thru 4th.
Wear and tear reduced and mileage improvement are just bonuses.

I had a 5-speed in my Charger for a minute with a 440 and a 509 cam and it was a bitch to run on the top end as it was surging in 5th gear @ 80mph because of the low RPMs (2300rpm)... I ended up swapping to a 6-speed with the Gen III hemi and it runs amazing - even at lower RPMs (cruising at 80 mph is ~1850rpm) and a steeper rear gear (3.55 swapped to 3.91) and it pulls through the RPM band really clean... just remember that with a lumpy cam you'll still need to turn some RPMs on the highway or you'll hate the manners the car has

I went with a Viper spec T-56 since I had one in my shed I bought a decade ago for $350... the T-56 Magnum is essentially just a TR-6060 with a mounted shifter like the T-56... just upgraded to the TR-6060 guts which are a bit stronger (similar strength to the older T-56 Viper trans which at the time was stronger than the GM and Ford variants)

rolling_Thunder said:

440 and a 509 cam and it was a bitch to run on the top end as it was surging in 5th gear @ 80

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I'm pretty sure I have the 292/509 cam, but since I put the 4.10 gears in with the 5 speed, I was never below 2,700 at highway speed. No problem here!

Cranky said:

Have even thought about running a GV OD. They seem to be pretty tough and might be an easier install.


Yup, don't care to buzz the engine all that much when on the freeway....and would probably not use 5th but a buddy of mine did. Can't remember what trans he had in it but he could run 1/8 mile or the 1/4.

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Yeah, absolutely, I didn't read all, I just thought " 1/4 mile & 11 sec".... after that, my brain shuts down