56 truck rearend

[coody]

what would the ideal rear end be on a 56 step? width? any thoughts?

[mr48chev]

Boy howdy you know how to wake up the Friday night crowd.

There was a time when we used tri 5 car rear ends under the trucks to get a 5 on 4-3/4 bolt pattern to match the 54 car front drums we stuck on the front but that is pretty well obsolete technology.

Things to factor in= How strong does the rear need to be?
Disk or drum brakes on rear?
bolt pattern for wheels?
mini tubs if needed or ain't no way on mini tubs?
The almighty $$$$$ involved.
Wheel/rim and tire choice.



I hate seeing guys throw out ideas for high dollar pieces when they have no clue as to the budget the guy or gal building the truck has and unless they are wanting one of us to work on it we have no viable reason to know unless they offer it up front. I don't think there are too many of us who wouldn't call Curry, Dutchmans or Mosier for a rear end all set up if we had the spendable coin to do it. A lot of budgets don't allow for that and for a few that would be the whole truck budget.

I hate seeing guys buy wheels and tires at the beginning of a build because things change along the way but you have to know what offset you are wanting to run on the rear and what width of rim and tire to be able to know where the wheel mount surfaces of the axles need to be sitting in the wheel wells. Too wide and the tires are out past the fenders like a redneck 4x4, too far in and you need tubs on a tire that may not need tubs or worse yet the tire is too far back from the lip of the fender and looks goofy.

Disk/drum that's your choice entirely but most of us like to be able to stop.

[hogfarm]

mr48chev is right the budget goes right the window,I knew what I wanted,so I began the search for a Ford nine inch.I found on for $50.00 so I brought is home and cut all the mounts off.After I got it shortened,new axles,posi track,disc brakes,I had over $1800.00 and still had to get the 4link

Originally Posted by mr48chev

Boy howdy you know how to wake up the Friday night crowd.

There was a time when we used tri 5 car rear ends under the trucks to get a 5 on 4-3/4 bolt pattern to match the 54 car front drums we stuck on the front but that is pretty well obsolete technology.

Things to factor in= How strong does the rear need to be?
Disk or drum brakes on rear?
bolt pattern for wheels?
mini tubs if needed or ain't no way on mini tubs?
The almighty $$$$$ involved.
Wheel/rim and tire choice.



I hate seeing guys throw out ideas for high dollar pieces when they have no clue as to the budget the guy or gal building the truck has and unless they are wanting one of us to work on it we have no viable reason to know unless they offer it up front. I don't think there are too many of us who wouldn't call Curry, Dutchmans or Mosier for a rear end all set up if we had the spendable coin to do it. A lot of budgets don't allow for that and for a few that would be the whole truck budget.

I hate seeing guys buy wheels and tires at the beginning of a build because things change along the way but you have to know what offset you are wanting to run on the rear and what width of rim and tire to be able to know where the wheel mount surfaces of the axles need to be sitting in the wheel wells. Too wide and the tires are out past the fenders like a redneck 4x4, too far in and you need tubs on a tire that may not need tubs or worse yet the tire is too far back from the lip of the fender and looks goofy.

Disk/drum that's your choice entirely but most of us like to be able to stop.

[dsraven]

I would say you should always try to get the best "base" you can afford because it is a bit of work to get the diff under there and all hooked up and operational. if you go with too light duty then it may work for you for awhile, or forever, but if you decide later to do something different and the diff won't handle it then you do the hunt and swap all over again.
when i set up my first 57 frame I went with an A10 axle and got it mocked up. I found it was not going to work for me plus I was worried about the possible swap to bigger power at a letr date. then I went with a camaro 10 bolt, found it to be basically the same as the S10 plus it was too wide for my plans. I ended up with the ford 8.8 because the 9" ford stuff was either wore out or waaay too much for my build budget. I ended up with the ford 8.8 because it is relatively easy to find and that makes it cheaper and easier to find something good at the pick n pull yard. parts are readily available if you want to freshen it up before final assembly. it is a pretty tough axle that comes with the ratio I wanted, 3.73, and also has a posi, large axles, disc brakes with an easy hook up for park brake. I know it will take a hammering and keep going. a friend of mine had big hp in a mustang with this diff and he did nothing to the diff other than a new reinforced diff cover. I had my truck set up for a 4.8l LS engine but knew if I changed my mind I could put big power to the 8.8 and if I did end up having trouble there are a few racer tricks that could be done without swapping the housing and starting all over. the ford pattern axles were easy to change over to the chevy pattern with chevy sized wheel studs drilled into the axle flange between the ford studs so it was easy to match the mustangII front end with the small chevy pattern that the frame has.
so, end of the day, go with the best you can afford but try to build in longevity and upgrade ability. I always say "get the base right and build off that".

just my thoughts though.

[dsraven]

it would help to know what the pontiac diff is from. it is like saying your other car is a chevy. there are lots of chevys. haha.
what does it come from
what gears does it have
is it a posi
what is the wheel mounting surface to wheel mounting surface dimension
what does it have for brakes
do you have a history on it (gramma's car or it came from a street racer)
have you pulled it apart to check axles, bearings etc
have you checked parts availability for the basics, like a re bearing kit or an axle

[dsraven]

if you are budget minded there is the ford 8.8 option from a ford explorer (offset center section) or a mustang (centered) which will come with a posi, 2.73 gears and disc brakes. the bolt pattern will be wrong but that is fixable by yourself if you are so inclined.
some guys use the Camaro diff which is usually a 10 bolt and may or may not have a posi and/or disc brakes
I have heard a caprice diff has been used a few times as well
it sorta depends on what you want to end up with, the final purpose. is it a narrow diff for some big fatties out back, a regular sized tire for the stock look, are you building a go fast truck or a grocery getting daily driver, trailer queen, do you want a lot of dish in the wheels so a narrower axle, are you on a budget, don't wanna go walking the wreckers just wanna buy something ready to bolt in, don't mind getting dirty and grinding some brackets off?
we really need to know the final and what your budget is like. if you find something of the proper width for you and you run leaf springs you can always get the spring perches from a trailer axle shop and weld them on where you need them.
it seems like the ford 9" is getting harder to find these days unless you wanna buy a new one from aftermarket. same with the 12 bolt chevy stuff. you also need to know how to measure so you can compare apples to apples. from wheel mounting flange to wheel mounting flange works best because you know the actual width. some measure from the backing plates which can mess you up depending on the type of brakes the axle has on it.

here is a track width chart for you to peruse.

http://www.crankshaftcoalition.com/w...l_measurements

and another

http://www.carnut.com/specs/rear.html


here is a wheel bolt pattern cross reference for you

http://www.roadkillcustoms.com/hot-r...#axzz4w6u3Zw6d

here is a place to learn about the ford 8.8

http://www.therangerstation.com/tech...ex-axles.shtml


sorry, I was kinda rambling there........

[dsraven]

sorry, explorer is 3.73 gears, my mistake. typo.

[dsraven]

here is another blurb on the ford 8.8 and what it comes in.

https://en.wikipedia.org/wiki/Ford_8.8_axle

[coody]

the old six lug rear-end is 62" I have a late model Camaro disc that is 65".Its mocked up and from flange to inner fender is 4".so take an inch for the tire I have 3" to work with on wheel selection. From previous posts It would be hard to find a shelf wheel to use. that's why am looking for something else. Its just a weekend ride nothing fancy. Thinking of keeping everything Chevy so ford rear-ends never crossed my mind. I seen 5 spokes maybe 17"s on rear. Mustang has black spokes but after market to fit Chevy. Also from past posts on the type of setup trianglalur four bar setup, maybe go back with leafs. I would like to fill the well up with a positive offset like Camaros and vets. Also front sub frame from 72 firebird is what I will be installing. I like both of yalls input! I get to a road block and just post my issues and BAM! I get going again. Thanks!!!

[dsraven]

I would look at the leafs seriously as well. waaay less work and they are just fine for ride quality etc. a 4 link is great but do you really need one for a daily driver or weekend side? a lot of guys overthink stuff and then it takes forever to be out driving. if you went with a leaf set up you can always swap it out later if you want. meanwhile you were driving it sooner and able to enjoy it.
the wider diff is going to result in a flatter wheel face due to proximity to the outer fender lip. maybe do some measurements on the frame width, the box width (inner and outer of where the wheel fits) and then the diff width. leave some room for when the diff moves up and down or sideways and then see what the wheel offset and max tire width will need to be for everything to fit. mock it all up on paper and you can see it better and be able to figure out if you will need to tub the box or whatever.

here are a few pics of wheel offsets

https://www.discounttiredirect.com/l...fset-backspace

don't forget to look at the scrub radius when changing wheels and tire sizes on the front. it can change the whole feel of the steering, more or less feedback and that skittish feeling.

just my thoughts

[59chev]

I went with a second gen Camaro/transam 10 bolt. 3.23 gears and a posi. 62" drum to drum which is the same as the stock rear end.

[dsraven]

second gen would also have a large sway bar and possibly discs on the rear on the trans am. it was the WS6 I think.The WS6 rear disc stuff came on the later '77-81 WS6 Trans Ams or a similar system was used on Caddy Sevilles from about the same time frame. you would need to grab asll the parts from the car so you don't get messed up trying to find some obscure part for the brakes. they had a different style of park brake unit that needs to be set up properly when doing the brake job or it won't work right.
if worried about spring wrap with leaf suspension you could install the old fashioned traction bar or the newer equivalent.