HP limit for OD 833?

[sbh126]

I had planned on using an overdrive unit in my 440 duster build but now I'm being told the trans wont hold up. There's a good article on bigblockdart about an OD swap but it just says they'll work for medium HP builds. Thats a little vague in my book. Should I go ahead and get a normal 833 or use the OD unit I already have. At a 1 to 1 ratio what would my rpm's be at 75mph with 3.55 rear gears and 26" wheels. Do I even need an overdrive? Thanks for any help.

This is mostly a street vehicle but will see the strip occaisionally.

 

[RustyRatRod]

Run it til it breaks then put a Richmond six speed in it.

 

[sbh126]

As much as I would lone a 6 speed I highly doubt its in my budget. Unless your buying.

 

[mullinax95]

Your RPM would be 3440 that's a shade tight but you might not spend a lot of time on the HWY.

 

[74slnt6]

see http://www.csgnetwork.com/multirpmcalc.html

 

[mullinax95]

Speed X Gear X 336 divided by TIRE SIZE = RPM

 

[sbh126]

That calculator is pretty neat. I've been playing with different ideas and ratios for the last 30 minutes. I think I'll just use the OD I have and keep a look out for a normal 833 and try it out next time I need a clutch change. Just to see what I like better. The OD unit has quite a jump from first to second. 3.09 to 1.67. I like the deep first gear but after that...

 

[dgc333]

I have a ~370HP 360 with an A833OD and the gear spread is just not an issue on the street. Can't even imagine you even noticing with a torquey 440.

An I certainly like turning 2200ish rpm at 70 mph on the hi-way.

 

[340mopar]

The '75 cast iron 833OD whould have a stronger case than the aluminum ones if you wanted the strongest one you could get.


Chuck

 

[lil Scamper]

i have one of the od tannies in my 74 scamp, its a 5.9L magnum 400hp 430 torque, ive got 255/70 R15s (29" x 10.3") on my car with 323 and it stands up good to abuse and as said earlier the gear spread isnt bad with the torque, espesially if you can shift it. Also i have seen a challenger with a 765hp 572 hemi that used one of these od trannies and he said he had no problem, not sure how it wud handles alot of power with slicks if you plan to race though. with my rear end gears ive decided to convert to a standard gearset but with the 355 it wud make a nice combo, these od trannies have a really low 3.09:1 first gear, second is 1.66:1 (normal 3rd), 3rd 1:1(normal 4th), and 4th is 0.75:1

 

[392Mopar]

I'm sortof in the same boat as you, but not so much in the power department. I have a 318 with an aluminum OD 4 speed in my Duster right now and I just picked up a 360 with an iron '74 trans thats looks like it was just rebuilt. I'm running 3:91 rear with 28" tires and hope to be making close to 400HP and I'm trying to decied which trans to use. I dont see the hwy very often so I'm usually under 55-60 MPH, just looking for the best trans for the street, stoplight to stoplight.

Seeing as the iron trans is in such good shape, I'm probably gonna go with it and see how it does, then if I can live with it, I'll sell the OD or just keep it just in case. I here that due to the closer spread, the iron non-OD will be more fun for around town seeing as I only use 4th in the OD on the hwy.

I love those calculators too, been messing with it alot myself trying to deciede. Heres the iron tranny I just picked up...

Butch

 

[greenhornet]

Are these OD 833's really that tough??? I've got one, might just make my Valiant a gear jammer instead of an auto...

 

[EL5DEMON340]

should be fine use a good gl-4 tran fluid that is on the thicker side

 

[JR]

I had an aluminum case OD behind a beefed up 383 and SG 3.91 in a 77 lil red clone. This was right after high school, I beat the ugodly crap out of the trans. I dumped the clutch hopped the front end, raced every import I could get my hands on, 115 mph blasts down I5 from Seattle to Portland at 2am looking for freeway races, all the usual stupid kid with a big block stuff you can think of and I never had any problems with the trans. I did replace a few clutch a few times and the rear gears once.

I just found an iron case OD for $100 that I am going to put behind the slant in my 69 D-100.

 

[lil Scamper]

i got a standard gearset trans with an aluminum od maincase thats i decided im going to use, i dont drive on hiways that often either and would rather have the tighter spread around town, i left the standard trans with passion performance when i was at the nationals last weekend, my od wasnt really rebuilt properly and sometimes rans shitty because of it, theyre going to bush the case and check all the internals, i might go with their slick shift kit as well, the od was a nice trans but the closer spread will be more fun i think

 

[dgc333]

should be fine use a good gl-4 tran fluid that is on the thicker side

Gear oil tends to make the A833 stiff shifting. The best stuff I have tried is Penzoil Syncromesh fluid. I would imagine the stuff Passion sells or the manual tranny fluids from Royal Purple or Redline would be similar.