4 speed a833 OD or original 4 speed

[Cmuller0420]

Going through sourcing parts I am having a hard time deciding what to do...and hoping others would share their experiences.

I have an 833OD - do I modify to use this or do I find a true 4 speed transmission.

currently running a stock 360, will eventually rebuild and have a modest upgrade to high 300HP range, 3.55 sure grip in the rear.

I don’t do a lot of highway driving but would be 1-1.5 hour trips every now and then, more so a back road/around town driver.

input would be appreciated!

also with that power range, could I keep running 8.25 rear end or when I make the engine upgrade should I be moving to 8.75 rear end?

thanks!

 

[Chryco Psycho]

I have done a lot of 4 spd conversions & many have used the A833 OD version , most people love them , 1-2 didn't like them , the trans will stand up to the power you want to run through it no problem , the shift pattern is the same with either by inverting the 3-4 shift lever , , the shifts are wide rpm wise , so you have to rev it a bit higher before shifting but otherwise there is not issue running the OD , you do have to bend the 3-4 shift rod slightly to clear the trans crossmember as well .
First gear is lower with a 3.07 ratio , the OD is .71 so this is equal to a 2.52 ratio in the diff on the highway You will need to drill & tap the shifter mount bosses on the tailhousing to mount the shifter , you can use the OD belhousing or you can use the 4.80" belhousing if you trim the front brg retainer down to 4.80" , you cannot fit the the OD trans to the belhousings with the 4.35" hole .
The 8.25 diff could live OK , it just depends how you treat it , slicks on a sticky race track you will break the diff , street driving where the tires can spin most of the time you should be fine with the 8.25 diff .
If you are going to build a 360 I would look for a 87-92 , put the 408 stroker kit in it & use a roller cam the block is designed for & you will have the best LA 360 heads Mopar ever used .
Let me know if you have questions !

 

[fasjac]

Your description sounds to be just cruising mode for the most of the time. If you want to put it to the test occasionally then you may want to go to 8 3/4 rear. However, I think your existing rear will handle 300 hp at the crank with non sticky tires. If it’s an open axle. The 8 3/4 with suregrip or not will handle much more hp.
As far as the 3.55’s, that’s a nice ratio for what you’re doing. Run the overdrive 833 if you like it. It’s ok for that type driving.
I run an 8 3/4 3.91 ratio with a Tremec 5 speed, around 600 hp. Cruise the highway at 75mph at 2600 rpms. Get on it hard at times and does fine. IMO if you plan on stomping on it, put 8 3/4 in. It’s a very good rear end. One last thing, you don’t want to be worried about your rear end if you decide to jump on it from dead stop.
Good luck and happy cruising. How about a pic of the car when you have time.

 

[Cmuller0420]

Thanks for the input! Helps make a decision on which way to go.

here is the car 74 rallye 360/4 speed...slowly going back to factory , rally red, white top and interior

 

[fasjac]

I have seen the pics on the site. Super nice ride!

 

[fasjac]

Red with white is sweet combo.

 

[Cmuller0420]

Being a 74 it’s not the most popular choice of years, but the body is super clean and being a 360/4 speed from factory was a cool to find.

looking forward to getting the 4 speed back in!

 

[fasjac]

Yes sir! That’s a keeper no doubt. Those are/will continue to be valuable cuz they didn’t produce that many.

 

[Rob C]

The 8-1/4 is plenty strong for that power level. I’ve had one run in the 11’s behind a 400 B block. Don’t kid yourself, there plenty strong.