Back in the day, I used one in a 55 drag car.(301, Muncie crash box, 5.13 R&P, Posi) never broke it even though the axles were welded. That was the 1st narrowed rear end that ever I did. The axles were cut just inboard of the bearings, a section removed, both halves were center drilled and doweled together, chamfered and welded with a rotational mig welder that was designed to weld up crankshaft journals. It scares me now to think of running that even with 10" hard slicks, but who knew? For what you want to do it should be fine. I like the new bearings, especially axles. Also, unless you break it, abusing it, any problems usually give you several thousand miles of warning.
If I was going to spend the money to rebuild one, I'd put the cash in a 57 Olds. Olds was the hot setup for many years until Nascar started using the 9" Fords. I broke a spider gear in my 38 Chevy coupe (tri 5 rear) but I just welded it up. Can you break them in a race car? sure. They are not made of peanut ****er and will last a long time on a normal street driver. It got costly and difficult to find axle bearings for a while when you broke one in Keokuk Iowa on the road. I'd keep a spare in my traveling tool box. It all depends on how it will be used.
I too had a stock rear under my 55 and one under my 40 Ford too. Broke both of them. The one in my 55 gave up the ghost while racing it. I was running street n strip M&H tires and they hooked pretty good. Bye bye axle. I replaced it with a 57 Pontiac rear and that did the trick (for a while). The one in my 40 broke the spider gears, and that was just from fooling around on the street. I put a Ford 9 inch in the 40. Both cars were 4 speed cars. As long as you don't hook up hard, the stock axles should work fine. Pull them out once in a while and see if they're starting to twist at the splined end.
Wish it was as simple as a few hundred dollars to upgrade to a better rear axle! I have always upgraded when my build requires it, but I sure can't find $300 rearends. Seems like a good 9" Ford I can find for $100-$150 for the housing. Then add $300-$500 for a thrid member if it's a posi and has decent gearing, and that's a bargain if you find it under $500. Axles on top of that, if you don't reuse the stock axles. I think if it was a few hundred to upgrade; everybody would jump on it!
Carry a couple of rear wheel bearings with you...they will, in all probability, go out before the axles or gears will...I've put over 100,000 miles on my '40 Stude with a '57 rear end in it (that's me on the right-my bro on the left has a '57 rear in his, too ...even drove both to the HAMB drags twice (13 1/2 hours one way from home), raced 'em then drove back home...never had a problem with either other than replacing wheel bearings at least once in their lives... R-
I have a 57 Ford 9 inch rear end complete with brakes bolt right in a try 5 chevy 2in shorter than the chevy PM me maybe we can make a deal
When i want to Whipp on one I pull this one out. all old schold 327 Muncie four speed 9 inch rear end
As a kid me and my brother lived in these cars and we thrashed em regularly. Memory serving as that was 45 years ago-the rear was there after the trans and motors schrapnelled almost every time. the did lose an axle out the side once in a while and they were really bad to have a lot of wheel hop so that was prob the main thing that would be the culprit......
In the late 1960's the question was asked in HOT ROD magazine. as i remember the answer was the rear end would hold all that your 327 will hand it
The weak reputation for Tri-5 rear axels has been exaggerated over the years. They are really much better than what you hear. My 55 has had the same driveline since when I first built it in 1977. 283 bored to 301, 12:1 compression, 375/327 cam, Muncie 4 speed and it's original 55 rear axel. However, the rear axel was rebuilt at that time. The housing is the original 55, but the center section is from a 57, which is stronger than a 55-56. It also has Zoom 4:56 gears and new, (at the time) spider gears in it's open differential. The only things that have been replaced since 1977 have been the rear axel shaft bearings, (which are quite pricey). Lakewood traction bars were installed back then, too This rear axel has survived three summers of solid drag racing, (with street tires), my high school and college years and all of the rest of my fun times with this car, without any breakage. It has never even broken an axel shaft. In addition it has been recently been raced at a few vintage drag racing meets, such as the Byron Meltdown. It's not the quickest car, but with a best of a 14:07 in the 1/4 mile, (missing 3rd gear),, it isn't the slowest, either.
I never remembered the axles as being weak. The R&P were known to let go with severe abuse, also the spider gears. I knew a guy with a '57 with a tricked out 454 with the works, couldn't keep the rear in it and they were set up correctly. He spent some $$ and went with an upgraded 12-bolt. For near-stock applications, it will probably hold up fine once you go through it. Bob
My recollection is that as stated the early 55-56 were weaker, the differential side bearings may have been smaller I believe. In that case, if you used a carrier from a 57-64 this would be eliminated. I never had a problem with one but I never abused one either. I always switched them out for a different unit and normally a Mopar unit. That being said, if everyone discards them they should be cheap and easy to find. That would make it very easy to replace anything if it ever broke which I doubt it will from your intended usage.
spider gears were the week part as everyone states,but back in the day[pre internet] there was a fix using mopar spider gears and axles.had to be in a national magazine like Hot Rod because that and rod and custom was about all I could afford.would have been early to mid 70's magazine
I had a 55' with 265/3 sp./3.70 rear [ first car ], a 56'/292/3 sp./4.56 rear, and a 55'/327/4 sp./3.70 rear [ owned 18 years ] . All were posi's and were beat on pretty badly especially the 265. None ever broke a axle and I replaced one wheel bearing on the 327 car. I also had a 55' rear end in my T roadster, same story. I wouldn't hesitate to use one in your application and I wouldn't hesitate to beat on it once in awhile.
It is hard to beat the look of a black '55 210 2 dr sedan with torq thrusts! Don't know how you could possibly improve that!
They are good and will take a lot of abuse, 4 speeds will hurt them, if it has an automatic I wouldn't worry about it. Big blocks with big tires and 4 speeds should have a 9" to be dependable. The spiders of the single track rear ends are a weak link but they have to be beat on to tear them up.
If you do decide to replace it don't s**** the old one. Tri-5 rear ends are a direct bolt in replacement for those on us with '49-'54 Chevys trying to get rid of the torque tube driveline. I'm sure someone would love to take it off your hands (and maybe help offset the cost of your upgrade). Doc
Don't expect to be able to buy replacement wheel bearings, wheel seals, or differential components and have them fast. I can get wheel bearings and seals to "pick your location" after a lead time (warehouse and shipping dept delay) of 2-3 days from the source---to however fast you can afford to get it overnight from that timeframe, and if you can afford my employer's charges for all of that. By my parts sourcing experience, if you find a set of NOS or aftermarket diff internal guts, you're a whole hell of a lot more resourceful than me. I have a checklist of folks that I know to not call for that application. Also, keep in mind, not all my sources have drawn to that specialty application. The folks that make Detroit Locker and Eaton Posi do have a part number for a posi diff for that early open driveshaft GM application. Bottom line. If you ****ter an old drop out chunk GM diff, parts will not be around the corner or cheap. You're late on the list to be folks that blew one of those up while hammering the hell out of those cars. THEY got those THEN when the spare parts were more bountiful. Some things, you need to treat like your sore finger. Be careful of hammer usage.
Had a 55-57 rear in my 37 Chevy truck. Not sure exactly what year it was, but it was a leaf spring car so 55-57. With a 350/350 and the 3.08 gears it was a great driver and i never had any trouble with it. I liked the older style appearance of the rear.
I have a Posi in my truck,so far no problems! Without a tag,how can you differentiate the years of them to know which axle bearings or seals you might need? Width of housing is the same for all the years?
My avatar had the original housing but I had a 4:56 gear with a posi and Henry axles. I ran Goodyear L60 tires. It was my daily and street race car for years, however, once running slicks, it broke. I never ran slicks after that.
I never had troubles with the axles on my '56. I did reduce the spider gears to carbon steel Crunchberries one time though.
I broke a " FEW " 55/57 Chevy rear ends. Back when they were not that old and not worn out. The IDEAL rear end for a 55/56/57 Chevy is a 57/58/59 Ford 9 inch. Almost a direct bolt in. They are 2 inches more narrow than the original ( 1 inch per side ) and look a lot like the original ( if that means anything to you ). The 28 spline 9 inch is a lot stronger than the 55/56/57 Chevy rear end. Parts are way less expensive ... and easily sourced. Gear ratios from 2.47 to 6.50 are available. POSI rear ends are way more plentiful. WIN / WIN !! IF you get real serious ... 31, 35, and 40 spline setups are available. .
This is where a look over on ChevyTalk.Org will really pay off. Check the stickies in the 49-54, 55-57, and 61-64 forums specifically, and pay attention to member DZAUTO. He is THE authority on these rear ends, and a lot of other cl***ic Chevrolet topics. The 55-56 rear ends have specifics, as does the 57 by itself, the other 58-64 are pretty much the same; the major differences involve third member casting durability (55-56), bearing sizes, and axles, along with some minor differences. We'll leave the 62-64 Nova/Chevy II rear ends out; some parts do swap, but they are made of lighter components. Butch/56sedandelivery.
I only noticed one person mention that 409 Impala's raced with these rear ends... Posi's of course.....they were launching a heavy car at a 4-5000 rpm...and they held up I am sure they eventually broke...but 9 inches break, and I also broke an Olds/Pontiac. Make sure the bearings are good...when these ****ter now, the bearings or setup is not correct and the tollerances can be the culprit. Look at the Meltdown Drags video's on Youtube...MANY MANY tri 5's running them at this event and running them hard. Torkwrench and my brother are 2 of the many.
A mid 70s Torino 9" is the same width as a 55 rear, and justy needs new spring perches to install. The Ebrake cables from the 55 fit right in.
I have a tri 5 rear in my 47 Chev. I went with this rear end, as I've never had that many problems with them in the past. Then about twenty years ago, I broke an axle. I'm sure they aren't any easier to find now. Back then the wheel bearing for the tri 5 was over $50, the same bearing for a 9" Ford was less than $20. I've been thinking about putting a 9" in it this winter. The Ford stuff is newer and easier to find.
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