833 OD behind a 340?

[71blueduster]

I plan on putting the 340 from my Duster into my 67 Barracuda, and am wanting to put a manual trans in there instead of an auto. From the dyno, I calculated the engine made about 330 hp. Would an aluminum case over drive 833 hold up behind this or should I look for a standard 4 speed? A 5 speed conversion probably won't happen. Having the OD would be nice, but isn't necessary.

 

['64 Cuda]

Can't say for sure. There's people who say it won't hold up. Then there was a guy in one of the Mopar magazines who had an OD trans behind a big block in a Superbird. Racers Have used aluminum cases behind high power motors for a long time. I think the major concern with the OD trans is the face that the power goes through the cluster gear & then back to the main shaft when the car is in high gear where normally the input & output shafts are locked together. I've read this tends to wear the input bearing faster because most cars spend a lot of time in high gear. This is why the size of the front bearing is larger in the OD trans.

I'm planning to run an aluminum OD trans in my car behind either a 360 or a 408 (haven't decided which one yet), but I have a close ratio aluminum case trans that I can swap in if the OD trans fails.

 

[72bluNblu]

I've got an 833 OD that's going in behind the 340 in my Challenger. If it works out right, it should be making about 400 hp. I've asked this same question myself over at cuda-challenger when I was spec'ing things out. There's a few guys over there that have run 833 OD's behind 440's for years without issue. I suspect it will wear out faster than a regular 833, but how much faster is anyone's guess, it'll depend on how you drive it as well.

I'm guessing if you want a OD transmission you're building a street car, not a racer. In that setting, it shouldn't be a problem. As pointed out, one of the wear issues is a high gear problem, which isn't where most of the hard use typically is. I've heard of the aluminum casing wearing as well where the shafts are mounted, but this is again a long duration problem, not something that shows up after a trip or two to the strip. The main shaft itself is a little smaller, the OD isn't as strong as a regular 833. But for a 330 hp street car, that shouldn't be a problem at all.

The way I see it, I bought 2 833 OD's for about $350. Both are in really good shape, and cores can usually be had for between 100 and 200 bucks. Even at that price they're well under the cost of a regular 833. If they last long enough for me to save up and put a 5 or 6 speed in my car, they've more than done their job.

Here's a link to a thread over on cuda-challenger. I think it was actually a for sale thread, but if you read through it a couple of guys mention using OD's behind big blocks. One raced a duster with a 440 and an 833 OD for 8 seasons without issue...:shock:

http://www.cuda-challenger.com/cc/index.php?topic=42526.0

 

[dgc333]

I have an A833OD behind a 360 that is making approx 370HP in my 68 Barracuda. It had over 100k miles on it based on the odometer of the doner pickup I got it out of and I have put another 55k miles on it with 25k of those miles being the 360. Tranny is not showing any signs of distress.

I don't beat the snot out of it but I am certainly not afraid to light them up.

 

[mshred]

http://www.forabodiesonly.com/mopar/showthread.php?t=26816

check this thread out, i thought the 5 speed swap was too much and never going to happen, and then i looked into it...with the power your planning i think the swap would fit your needs perfectly...its actually alot simpler than you would think, and you could use alot of the mopar stuff, without the need to cut your floor for the tranny, not to mention a better overall gear ratio spread and overdrive...look through it and decide and if you do decide in favor of it give quicktime inc a call soon and ask to see if they have any of the clearance item conversion bellhousings left...when i got mine there was only 12 left...call em soon if your interested

 

[moparwedden]

I Have One Behind My 440 Duster. Its Only A Street Car And Have Had No Problems At All. I Have 391 Gears And At 70MPH Its At 2200RPM. Real Nice On The HWY. And Also Great In The Streets. Don't Be Afraid, They Do Work.

 

[GhostDuster]

It will work but the draw back of the aluminum case OD vs the Cast Iron cased OD...

is that in higher horsepower applications the wear due to flexing concerns to do with component in aluminim case...

a recall was actually done on some of the aluminum cased ones and they were replaced at the dealers with cast iron OD versions when they failed...

For the A body lines the aluminum case OD's were typically found behind the slantsixes in the Special MPG package cars because the extra weight savings that the aluminum case resulted in...

the Special MPG models were called "Dart Lite", "Valiant Lite", & "Feather Duster" these were 1 year only 1976 models EPA rated at 36 MPG

They also were commonly found in F Bodys from 76 and up.... but I do not see any reference to special MPG designated versions in them

except for that in 1979 a base package 225 equiped Sunrise/Duster option with the electronic lean burn/electronic Spark Control also were a high mileage design... generating 30+ MPG being possible in part high rear axle ratios of 3.21, 2.76, and 2.41

That said I really think it would depend on how it was driven. Driven easy no burn outs, no speed shifting, no slick shifting (reving engine til hitting right RPM then quick movement into gear without clutch use/racing shift Manuever), avoiding compression slow down when down shifting etc. Avoidance of these situations no problem...

But to be safe I would find a cast iron case or put the OD parts in the cast iron case...

The front bearing support area at front of trans is larger on OD so to use your bellhousing you need to have the hole machined to accept that larger hub not a big issue any machine shop can do it for you

Walt

 

[dgc333]

is that in higher horsepower applications the wear due to flexing concerns to do with component in aluminim case...

Its not so much the case flexing as the counter shaft bore in the case becomes oblong and allows the gears to seperate. Eventually with the improper mesh there is gear failure. You will get leaks long before a failure. And there is a relatively easy fix by having the case bored out and a bushing pressed in.

But, as most everyone that has done it they actually stand up quite well.

 

[Outsider]

Racers Have used aluminum cases behind high power motors for a long time. I think the major concern with the OD trans is the face that the power goes through the cluster gear & then back to the main shaft when the car is in high gear where normally the input & output shafts are locked together. I've read this tends to wear the input bearing faster because most cars spend a lot of time in high gear. This is why the size of the front bearing is larger in the OD trans.

The aluminum cases that were used for racing were offered through Direct Connection. They were purpose built Prostock cases. These cases were fully bushed for the countergear shaft, and they were stronger cases.
In all 4-speeds the power goes through the input shaft to the countergear (cluster), then to the mainshaft. There is no output shaft, the mainshaft would be what you are calling the output shaft.


71blueduster,
Without the transmission case being bushed, the "cluster" gear shaft can "flex" forcing the hole in the aluminum case the shaft passes through, to become out-of-round. Being out of round causes movement in the cluster gear which can lead to gears not meshing correctly and once again catastrophic failure. THIS CAN HAPPEN WITH ONE BURNOUT...or, over a longer period of time.
The only thing I use OD transmissions for is to scavange small parts from.

Now I wrote this with a 5 year old crawling all over me, so I hope that I got that all correct. #-o

 

[Outsider]

Its not so much the case flexing as the counter shaft bore in the case becomes oblong and allows the gears to seperate. Eventually with the improper mesh there is gear failure. You will get leaks long before a failure. And there is a relatively easy fix by having the case bored out and a bushing pressed in.

But, as most everyone that has done it they actually stand up quite well.

Sorry, I didn't see your ecellent post.

 

[mshred]

I plan on putting the 340 from my Duster into my 67 Barracuda, and am wanting to put a manual trans in there instead of an auto. From the dyno, I calculated the engine made about 330 hp. Would an aluminum case over drive 833 hold up behind this or should I look for a standard 4 speed? A 5 speed conversion probably won't happen. Having the OD would be nice, but isn't necessary.

have you made a decision as to which route your going for the tranny?:clock:

 

[71blueduster]

have you made a decision as to which route your going for the tranny?:clock:

I'll probably just go with the 833 OD. I'm not worried about the Barracuda being fast or anything. I just want it as a cruiser that I can drive anywhere with. The Duster will be the fast car after I swap the 440 into it.

 

[mshred]

cool...goodluck with it and keep us all posted!