Hello all! New here, and fairly new to Mopar's and /6, only had the car for a year. After previous years of mostly driving manual, I'm kinda sick of the auto in my Valiant. So, I was wondering, what exactly I'd be in for if I tried to change it to the 4 speed. Originally I was also thinking of putting a 318/360 in as well, but eh, now I'm thinking that keeping the 225 /6 would be enough, even if I had to modify it.

Anyway, in terms of keeping the /6, would I be able to use the current block, or should I go hunting for one that was mated with a 3 or 4 speed manual?

Would it be worth saving up for a whole kit from here? https://www.passonperformance.com/ Or should I get just their rebuilt trans and search elsewhere for other parts? Or just try to find a cheap one somewhere else? Their listing for 23-spline shows 3.09, 2.66, and 2.47 low gears available, whereas, as far as I can tell, the short-tailshaft versions from the factory only came in 3.09.

Rear end? The codes say the car has a 2.76 rear. And I'm pretty sure it's a 7.25 (small bolt pattern). Should I move to, say, a 3.23? If 3.09 is the only kind available, should I leave the 2.76? The rear axle has a bit of bearing rumble (though it has not worsened at all since I bought it 10k miles ago). Would the 7.25 be enough if I leave the /6 if it's fixed (and converted to 5x4.5), or should I hunt for an 8.25?

Perhaps would modify the /6, not sure yet. If so, it would just be a mild edit, I'm not trying for some "250hp at wheels!" thing. I intend to keep it a daily driver so nothing too wild. (Currently it has the super six intake [which it already had when I bought it] with a Motorcraft 2150 but is otherwise unmodified)

I'm just trying to figure out pricing and work before I buy a single item, thanks for any input.

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First off, very nice looking car.

I had an a833 OD trans in my Duster that had the 3.09 first gear. I broke the 7.25 axle that had 2.94 gears. I replaced it with an 8.75 with 2.76 gears. The 2.76's were way too tall. It took a lot of clutch slippage to get underway especially on any kind of hill. I don't recommend that combo. I swapped to 3.23's and it was much better.

If your budget is large, I would recommend ,as the ultimate set up, an A833 OD trans with a gear vendors OD after that. An 8.75 axle with 4.30 or 4.56 gears. You would have a double OD and the ability to manually split the gears effectively giving you an eight speed trans.

That would be a lot of $$$ but a great set up.

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1976 Feather Duster /6 4sp
1984 W100 318 727 np241
1972 'Cuda 340 4sp
1985 D250 360 46RH

3.09 OD with 4+ rear? Wow.......so 4.30 with the OD A833 would be like a non-OD with 3.13...and with the gear vendors that becomes 2.45....3.33 and 2.6 for 4.56 rear...Interesting.

"First off, very nice looking car." Thanks! Though, she doesn't look so good closer than that...jesus christ why did someone paint the hood black, they even painted over the chrome letters!

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If that car were mine, I would put in a late 80's a904 with lock-up converter from a truck with a gear vendors OD after that and then run 3.55's in the rear end. If you are not dead set on a manual trans.

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1976 Feather Duster /6 4sp
1984 W100 318 727 np241
1972 'Cuda 340 4sp
1985 D250 360 46RH

I'm not really looking for huge performance...I want a four speed, eheh. The only reason I'd put in another 904 is if the current one breaks and the manual conversion isn't feasible.

A gear vendors probably wouldn't be worth the cost in a daily like this...With the 833OD + Gearvendors setup you suggested, I would probably end up just starting in first, switching the gearvendor's to OD, and leaving it there for the rest of the transmissions shifting. On the grandparents 390ci + 4spd Mustang, that might be worth the cost, but I'm not so sure on this Valiant, especially if I leave the /6.

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Your budget will determine the likelihood of the conversion....

You will be looking at cutting a new hump for the shifter in the tranny tunnel and if you want it to look good, you're going to want a new 4 speed carpet set, and tearing apart your under dash to install the clutch pedal set. You will also be popping for a 1967-1976 set of linkage, ballstuds, Z-bar, bellhousing, clutch fork, inspection plates,driveshaft yoke if the transmission uses the A-727 yoke) and a flywheel.

Your block will be able to take a manual tranny, just need to remove the convertor to determine if it needs a pilot bushing or already has one.

"Direct" 4 speeds are getting spendy, the A-833 OD is not as spendy, but 90% of the boxes that can be gotten out of junkyards will need a full rebuild.

For performance the best first gear ratio for a nice leaving ratio is 10:1... 3.09 and 3.55 is about as good as that will get... 3.55 and an OD presents a very nice highway ratio for mileage.... the down fall is that the rpm drop between 1st and 2nd in that tranny is huge (and gets worse if you decide on a 4.xx rear ratio)...but it will make a stock or RV cam build feel very sporty....

Fair enough, I was aware of the tunnel cut.



So should I look for an OD version and rebuild if needed? I've never done transmission work before, though, so I'd probably need help. How about that site I linked in first post? Anyone have good/bad experiences with them? They ask $1,000 for a rebuilt non-OD 23 spline



Huh, yeah, the 3.55 would work, in the OD gear it'd be lower than a non-OD with 2.76 rear.

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Some on here have installed a Borg-Warner T-5 with success. That may be an option also.

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1976 Feather Duster /6 4sp
1984 W100 318 727 np241
1972 'Cuda 340 4sp
1985 D250 360 46RH

Yeah I saw , but a lot of the images don't work.

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If you want the 4 speed, start looking for a complete car or wrecked car that had a decent transmission in it already. Complete setups show up from time to time.

I would go at least with a 3.55 or 3.91/4.10 gear with the OD transmission

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

I did find This, though I'm not sure if it's good or not.

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that would get you almost everything in one shot...

I wonder if the trans hump could be adapted to his A-body tunnel?

If the guy still has the car that you could cut the trans/shifter hump out of, that would be an additional piece you wouldn't have to go searching for.

Roger

Dya think I should go for it, or look around more?

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Would the F body pedals work in an A Body??

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6