So I have an 80 Shortbox with a /6 833/od. I plan to swap the slant for a 383 est at 510hp. Was planning on a 727 bit just had the idea of leaving it a manual. How much hp can the 833/od handle also abuse. What can I do to make the trans handle the 383 thanks.

The biggest downfall is the alum case and that the countershaft isnt bushed.. I have ripped some darn hard 1 2 and 2 3 shifts in my shorty. The tires have spun before any damage has happened.. I definately wouldnt drag race it.. Your biggest problem is gonna be finding a bell with the 5.125 dia hole and the 833/od833 bolt pattern..

Ma Mopar did have a truck bell that had the 833/od833 NP435/445 bolt pattern but they are rare and expensive..

There is no definitive answer, as it depends on the setup. Remember 57Plymouth that used to post? He had a stout 340 in a LRE clone that broke his. I am going to start testing the limits myself though. I have a big block and the general concensous is it probably puts out 400-425 HP and 450-480 Tq. The torque input (what most trans nowadays are rated by) and what you make slip (tires or clutch) are going to be the key to making it live---along with how you shift it, which I say powershifting will eventually blow it apart (shocking any drivetrain parts will eventually take thier toll).

Right now my street tires are definatly my limiting factor. I can spin easily through first and second---even on the track. But what what will happen when I put something more sticky on??....

FYI, you can turn the big 5.125 bearing retainer down to the second bigger 4.807 size so it fits a standard big block bellhousing--or just swap retainers as long as your O/D trans has the 308 front bearing which has the bigger bolt pattern.

"....The biggest downfall is the alum case and that the countershaft isnt bushed...."

I agree and have seen more than one cracked case to prove it (they do make good dummy/mockup units when you gut them however LOL).

I'm not sure what years, but Chrysler did make some of the overdrive 833s with an iron case. I believe they were used exclusively in trucks. I'm using an iron case one in my 57 Plymouth behind a 1st Gen Hemi. I'm not sure, but I believe Brian (57Plymouth) was running an aluminum one in his LRE.

They have a blowproof bellowing available. That's what got me thinking about it. It will see track time. I like the idea of jamming the gears.

Just for giggles. What would it take to install a Hemi 4 speed into the truck? (18 spline IIRC)

I may be able to line Harry up with a guy selling one.

Can I afford it

What Flywheel would I need? I already javelin an aftermarket bellowing and a flywheel I got to put behind a 440 with an NP435.
Would it be better to track down a car bellhousing? Price would most likely be the same or a bit less?

Finally going to Tennessee or is his shop too small now

So I assume the bellhousing you have then is a steel safety style one and only set up for the 435? If that is the case, I have to assume that you can land the top bolts of an 833 on the belhousing and drill those holes out and weld a nut on the backside. The lowers will need tabs more than likely welded to the bell to capture those bolt holes.

I made up a 1/4" plate years ago for when I was using a aluminum 435 factory bell to an 833 trans. On that bell as I said above is what I experienced in bolt hole alignment. I made it work, it seemed to be fine. I had the 1/4" plate bored for the 5.125" front retainer size, you could do it to any size retainer you see fit really. The whole trick with any of this is dial indicating the register for the trans to the back of the crank to get them as close as possible to line up.

On your flywheel that you already have for the 440, as long as its an internal balance and you balance the 383 for internal balance it will work. If you have a external balance 440 flywheel already, you will have to have it rebalanced per your rotating assembly---which most likely means having weld added on to your flywheel or a small slug of mallory metal added to the appropriate spot.

If your flywheel is for an 11 or 12 inch clutch, make sure the bellhousing will fit around it when bolted to the engine and that the starter also lines up. Some bellhousings will only accept the smaller 10.5" clutch flywheel and starter location.

The obese I see for sale are for several applications not just one. I purchased mine used from an RCC member and have yet to pull it from the box. If its Only for the NP435 than I will locate what's needed.
http://www.summitracing.com/parts/lak-15335/overview/make/dodge

I was told 383-440 are balanced the same. Is a 69 440 and 65 383 Both Forged. I got the flywheel and bellhousing together. Im still slowly gathering parts for that build.

i have a friend that rebuilt his 833 od with the passon hemi performance gear set--it is handling 1000 hp at the strip---the build kit ran about $1800....bob

Hah Not paying $1800 for a kit. Id be better off with a 5/6spd for that kind of money.

if you limit the hot runs to 1st,2nd gear you should be ok---the weakness in the OD is that 3rd,4th gear are switched on the main shaft---if you arent stressing them out you should be able to have some fun...