I've probably asked this before, but I've slept since then. So, forgive me for being redundant.
I want to increase the towing capacity of my '86 Camino (305/4 sp auto) by installing a 373 rear end in place of the 270 something. I would also add a heavier duty radiator and I already have a transmission cooler installed.

I need to pull about 3,000 lbs. Right now my Camino couldn't pull the hat off your head. Will the rear end swap help me meet my towing goal?

The short answer would be - yes, the lower rear end will give it more pulling power.

BUT What about stopping and controlling that much weight if it starts swaying. I wouldn't even think of towing as much weight as the vehicle itself weighs. You will need lots of enhancements - especially some GREEEEEEEEEEEEEEAAAAAAAAAT trailer brakes.

Hey Thanks
Yes, I know it's a lot of weight but the trailer I'm wanting to pull is perfectly balanced and pulls like a dream. I would probably add electic brakes to the trailer also.

I was mostly concerned about pulling power, overheating, and transmission capacity. I wouldn't expect to pull in overdrive.

Any other opinions or suggestions?

Electric trailer brakes. external transmission cooler, heavy duty radiator, rear air bags, minimum of a class 2 hitch. Pulling is the easy part, stopping will be the challenge.

Does anyone know for sure what ratio rear end would be in my '86 Camino 305 with a 4sp auto OD?

Somewhere I thought I saw it being a 270 something, but now I can't find anything to confirm that.

Look on the SPIL in the glove box and you will know for sure. Should see something GU1 or something similar to that. GU1 = 2.41, GU2 = 2.73 ratio. There are more but not sure what you have so if you find it you can tell exactly what you had originally. You can also find a set of numbers and letters on the axle tube itself that when decoded will tell you.

Hey, thanks a bunch. I'm going out now to check out what you suggested.

The only "G" I have is a GMB. Any other code I might look for?

Nothing else that starts with a G what about with a H maybe there are some listed under that also. That would not be a GM8 by chance would it?

GMB PLANT CODE GM DO BRASIL LTDA, BRAZIL

I'll take another look at it.

You were right: It is a GM8 not a GMB

GM8 axle rear 2.56 ratio

Wow, that's pretty high. Thanks so much for your help.

GM8 axle rear 2.56 ratio

wow and i thought my 2.73's were bad, looks like we are both looking for new gears.

may i suggest a higher stall converter ? :dontknow:

you dont need a stall to tow with that will only amplify the heat problem you need good brakes dont forget the rear brakes these are often overlooked but easily upgraded as well woody out

Has anyone converted from a 2.56 to a 3.73, and how was the performance?

I RECENTLY DID THAT SWAP AND ITS LIKE NIGHT AND DAY BIG IMPROVEMENT OVER STOCK ALSO GOT A EATON POSI IN THERE GOOD LUCK:beer:

Hey Bill,
I found this Monte in a salvage yard in Pasa-git down-dena a few weeks ago. I remember Annette, the parts gal, saying that it has a posi rear end. didn't mention the gearing. You might want to give her a call and see if she can help you out. For a fee they will pull the rear end and have it ready for you to pick up. Just so you'll know, I'm the one that bought the t.v. from you. Oh Yeah.. God Bless Arizona!!
1985 Monte Carlo SS (Pasadena)

Date: 2010-09-07, 12:33PM CDT
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Cannot sell whole car. PARTS ONLY!!! 5.0L V8 engine. Front clip will be sold together for $750. If interested in any parts, please feel free to contact me. Tuesday-Friday 8:30-3:00 and Saturday 8:30-4:30. 713-473-1717 Annette


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Has anyone converted from a 2.56 to a 3.73, and how was the performance?

that will make a lot of differance...youll think u got a bbc,, for a while:poke:
what radiator do u have??how many rows of tubes??how wide are the tubes??
get a good brake controller,,it does make a differance..
there is a front brake mod,,using b-body parts,,rotors,calapers,spindles,a-arms...:texas:

Has anyone converted from a 2.56 to a 3.73, and how was the performance?

I plan on doing this, but not until I get an OD tranny in as well. Mine's not nearly as bad... I got a 2.73 gear set.

Don't remember the rear drum diameter on a 5th gen. The 4th gens had 9.5" thru '75, and went to 11" in '76 &'77. I believe it's the small 9.5 inch on yours.
Bound to be some after-market up-grades for those. Even the 11" will need some brakes on a trailer.

A place called Master Power Brakes has a disc set-up for your rear brakes, but it's $850 bucks. They don't show any bigger drum set-up.

JJLT1,
I have 3 rows of tubes and they look to be about 1/2" wide or a bit wider.

Hey, I really appreciate all the help and advice you guys are giving me. I think I've got a line on a 3.73 rear end, and will hopefully be going forward with the conversion soon.

a 1/2" 3 row should be ok,,if its clean,,and every thing else is in good shape...
i had a 3row in my 90 4x4 350/700r4/3.42s,,,pullin 5-6k...
.
i dont know about a 200-4r,,but
the problems with the early od trans (700r4)was the lockup torqconverters,,
they could not handle the towing...i have a switch to disable the lockup,,,
(later i think they made the clutch in the converter bigger)
see what the trany xperts say?? big trany cooler is a must..
.
i tryed one of the electronic brake controllers,,never could get it right..
it works on an adjustabe time delay/brake force curve,,i did not like it at all...:texas:

I had an electric brake controller on my '88 van, which seemed to work by inertia. It had to be positioned correctly for it to work right, but it did work good for puling my boat, which is a 26 ft mahogany cabin cruiser.

yea Bill,i bet that 26 footer was lite.
i have a electric controller now,,(tekonshea? 2030)had to go look..
with manual controls,,works great..it has the pendulum,and works on inertia,,
set the initial brake force,set the level,,good to go..it works so much better i forget its there..
you can play with the level wheel on the bottom,till you get it just right for city/hiway..
the electronic one,was a pita to program...pull over,get out the manual,find the setup mode.......:texas:

I tow a 3000 lb. camper with mine. I changed the rear out to 3.08 gears and added a trans cooler. It all ready came with a tow package which had the big radiator . I use a sway away sway control arm for the camper , and it pulls like a dream. The electric brakes are a must, plus I use air lift air bags to level out the camino. I some times haul my 4 wheeler in the bed while I pull my camper, no problems. I have a 78 with a original 350 and th350 trans.