what are you going to use it for ...i have had 57 chevy in 2 cars a 33 dodge with a 44 0 an d auto trans and a austin healy with a 462 bb chevy with auto trans for a street car on street tires no problems ...on the drag strip with slicks you need a 9 inch or a dana ...but that's just me..
Just a street car. With a 3.00 gear and street tires, I am not worried about it anymore. I just went and measured a 4.56 Chevy gear set I have for sale. Guess what. The ring gear is exactly 8" OD I think the rears are exactly the same strength. The 62 rear end lasted 20 years with no problems. I am good to go!
I think Andy said he will be running a 350 which is capable of more power than a 301, but the 32 should weigh less. That must have been fun with 4.88 gears. A 55-57 Chevy rear is approaching 70 years of age. Given the immense popularity of these cars in the hot rodding world, you have to consider that many surviving rear ends have suffered some type of abuse during their lifetime. They were never considered to be one of the stronger rearends available and often were replaced with something stronger. When someone builds a hot rod that they expect to drive in a manner similar to how you say you drove, its wise to start with a rear that is stronger rather than cheaper. Engines today routinely produce more power than what your 301 probably produced. If you were getting 300 HP out of a 301 back in the day, that was considered pretty good.......1hp per cu in. Today, 300 hp isn't much more than a cruizer, and it doesn't take 6500 rpms to get there. So what works depends a lot on what the builder plans to do with the car when finished. Andy stated that he does not abuse his cars and merely wants something to daily drive/cruise. In that case, he should be fine with the Chevy rear end. Myself, I would want something that would offer not only the ability to handle my occasional adrenalin rushes but the rather large tires my 32 will have.
Yes, many people like to brag about what they have........ To me it's not a matter of bragging, I just decided ahead of time that the 9" Ford (or even an 8.8) is a better starting point for what I want to build. Many people pick various rear ends because they can install them cheaply and maybe they even have the correct bolt pattern. Often axles in these smaller rear ends aren't very strong and sometimes they are only retained by clips rather than real bearing retainers. More than once those type axles have failed and let a wheel come off the vehicle. So I look at the big picture and plan ahead. In that vein, I found that while 9" rears got expensive, the availability of the 8.8 has helped bring those prices back down. A year or so ago, I bought 3 9" rears locally in one day for about $150 each. One even has 3.70 gears. I like the ability to have different third members available with different ratios that I can switch out without having to "set them up every time I want to try a different ratio". The finished "pumpkins" are easy to sell and recoup my money if I decide I don't want that ratio any more. If you have several cars, that works out pretty nicely. Throw some 4.56 gears in and go to the strip for some fun.....then plug the ole 3.70s in for daily driving.....and I can do that with all the vehicles. I like the fact that the axles are retained by a real bearing retainer and won't leave the housing if I break an axle. I think the 55 Chevy has retainers but some of the other popular Chevy rears don't. I also like the strength of not only the gears, but most of the axles. Generally they need to be narrowed. So I built a jig to do that myself. I made some dummy stubs (from old axles) that fit the housing and let me test fit wheels and make sure my calculations and fab work are correct before I shorten or order new axles. I'm not interested in bragging, I'm interested in building what works best for me, and the interchangability it allows for me. Current plans call for an engine that is very streetable but produces torque in the 600+ lbs/ft range. I bought a transmission that is specifically designed to handle 700 lbs/ft of torque. And, I want a rearend that can handle that power. Naturally I will want to visit a drag strip and see if it performs as well as I would like, and probably try it with some different gear ratios just for fun before settling into a good street ratio. I don't think I need to brag about my rear end as I'm building the car to be what I think is my vision of a hot rod........and I don't really care whether anyone else likes it or not. To me its about making the best choices for what I need....it's as simple as that. Andys needs are apparently quite different from mine, so he doesn't need the same solution.
I was OK with the Chevy rear. The 350 ran strong. 327 heads, Isky cam, 64 Vette injection, 2 1/2 exhaust. I bracket raced it a lot. It was consistant with the FI and auto. Never had slicks. The FI was instantanious. Fun times. That was 50 years ago. I just putt around now. The engine is the same except the FI is gone. I have a old set of 2x4's I might run or a tunnel ram I made in 64. I sure would like to get it running again. Here is a pic from 73 getting the Christmas tree I
My '41 P/u has a '55/'56 rear in it and it's fine except for one thing. I'm having to replace the bearings on it and it's A LOT harder to find quality bearings that don't leak (think old NOS or NORS) and a '57 is a 1 year only. I've been reading up like crazy on these rears and people still beat on them without problems in they're modified tri-fives. I also have a slightly noisy $200 8" under the Lark Wagon that works fine. I have a 9.3 going in the A......
The issue with most lighter built rear differentials is traction. The better the car hooks up, the better the odds are it's going to break. So if the plan is much HP and sticky wrinkle wall slicks, then either axle is going to be a bad choice. But if you keep the tire width to maybe a 9" wide or less, and you're not building huge HP, then either will hold up fine for most cars.
my brother and i built an altered cl*** t with a 302 sbf. when he bought the rolling project it was slated for the street. it had an 8" in it. he bought custom axles, a spool and 4.10 gears. it runs 10" wide slicks. i know this isn't the same thing the op is asking for but, this t is a 10.90 car for the last 10 years and no problems have happened. also, the car weighs 1650 lbs.
I've been putting the venerable 9" Ford under lots of present and past cars. I had one in my '66 Nova, narrowed and I moved the leaf springs inboard so I could run bigger slicks. Of course the Nova stock car, I told the tech guy it was a '55-'64 Chevy rear. The next owner got formally busted with it when he ran the car. My regret with my Ford was not going with a bigger series yoke, I kept it as a 1310 since that was what I had with the old pumpkin I ran for a while.
56 Chevy rear in my 36 since 1960.... all with different sbc engine never over 400 hp. New bearings seals etc and a new pinion bearing is all that's been done.
[QUOTE="2OLD2FAST,]never a rear differential problem .[/QUOTE] 2OLDFAST Quote: Curious as to why you made the ***umption that my 301 would only be capable of 300 HP ? A 302 Z28 from the same period was recognized as having 400+ HP ? Lets take the second statement first......"A 302 Z28 from the same period was recognized as having 400+ hp. The factory "rated" the engine at 290 HP @ 5800 rpm and 290 lbs ft @ 4200 rpms. Granted, that was underated. But they did not make 400+ HP. There were "rumors" of 375 hp @ almost 7,000 rpms. Not many people do that in their daily driver and those engines were also "race prepped". Further, one of the "lovingly applied" jokes was that the 302 was referred to as the "NotATorqueMonster". Virtually everyone knows that when you cam an engine to get HP at high rpms, you give up low rpm torque and often the mid range driveabilty as well. I imagine thats one reason your 3300 lb 57 Chevy needed the 4.88 gears when slicks were on it. The 68 Camaro in race trim weighed 300/400 lbs less than your 57. Another thing to consider is that these cars were designed to "road"race, not "drag race", so low end torque was lacking. Thats why the purist like all the nostalgic period correctness of a Z28 and the guys who actually daily drive Camaros liked the 350s. Torque is what breaks rear ends, and the 302 is not and never was a torque engine. The BW T-10 was probably the weak link in your drivetrain and protected the rearend as well. Probably much smaller slicks than what many use today as well. So I'm not knocking the Chevy rearend for moderate use, but how many people do you know who have removed a 9 in Ford just to replace it with a 57 Chevy rear end?
My roadster ran a 55 Chevy rear end for 50 years; behind a warmed-over 331 Cad with an early Hydro. The original builder broke spider gears, his son blew the ring gear, the guy I bought it from broke spider gears. I pulled the rear end apart a couple of years ago when I started the complete re-do of the car and you guessed it... broken spider gears. It's got a 9" now.
My 63 Impala had a posi with 4.11 gears with a M21 4 speed that ran mid 14's with 8" slicks and I never blew the rear end, I ran it hard but never was stupid with it, like side stepping the clutch or 6000 RPM launches. After 75,000 miles the axle housing did break. I am currently building a 58 Chevy with a mild 350 and it is running a stock rear end with 4.11 gears am not the least bit worried about it holding up!
2OLDFAST Quote: Curious as to why you made the ***umption that my 301 would only be capable of 300 HP ? A 302 Z28 from the same period was recognized as having 400+ HP ? Lets take the second statement first......"A 302 Z28 from the same period was recognized as having 400+ hp. The factory "rated" the engine at 290 HP @ 5800 rpm and 290 lbs ft @ 4200 rpms. Granted, that was underated. But they did not make 400+ HP. There were "rumors" of 375 hp @ almost 7,000 rpms. Not many people do that in their daily driver and those engines were also "race prepped". Further, one of the "lovingly applied" jokes was that the 302 was referred to as the "NotATorqueMonster". Virtually everyone knows that when you cam an engine to get HP at high rpms, you give up low rpm torque and often the mid range driveabilty as well. I imagine thats one reason your 3300 lb 57 Chevy needed the 4.88 gears when slicks were on it. The 68 Camaro in race trim weighed 300/400 lbs less than your 57. Another thing to consider is that these cars were designed to "road"race, not "drag race", so low end torque was lacking. Thats why the purist like all the nostalgic period correctness of a Z28 and the guys who actually daily drive Camaros liked the 350s. Torque is what breaks rear ends, and the 302 is not and never was a torque engine. The BW T-10 was probably the weak link in your drivetrain and protected the rearend as well. Probably much smaller slicks than what many use today as well. So I'm not knocking the Chevy rearend for moderate use, but how many people do you know who have removed a 9 in Ford just to replace it with a 57 Chevy rear end?[/QUOTE] Youre the expert . BTW were you drag racing in the mid to late 60's ?
O/P you will be fine with what you have and want to do. If you ever plan on making any real hp or drag racing get a real rear end.
Nope, not an expert by any means, but someone who does try not to exaggerate things. One of the first things many early hot rodders had to learn was that if you wanted the most HP out of any engine, you got there by giving up torque and driveability. Many people have installed wild cams in their street car only to be disappointed with the performance, and later switched to something milder. Thats why cam manufacturers make different versions of their camshafts. I don't have to be an expert to grasp the basics. Was I drag racing in the mid sixties........You bet I was. In fact I was street racing in the early 60s.......60-61. Mid 60s was when muscle cars began taking over. And my son's first car was a 57 Chevy which we still have. And it has the stock rear end still under it.
It's not horsepower, it's torque that kills rear axles. Ford limited the 8" to 302 or smaller motors (OK, they did put it behind the 351 in a few cars in the very late '70s, but it was only making 302-level power by that point), anything larger got the 9". Keep the torque at a reasonable level and avoid extreme use (sidestepping, slicks), you can beat the hell out of an 8" with no fear of breakage. What may fail over time is the pinion bearings, that was/is the main weak point in terms of longevity in 'normal' use, excess torque can accelerate that wear.
More anecdotal evience: I had a '55 - '64 Chevy under my T bucket 327 SBC roadster w/ 4.11 posi. Not sure which year it was. I actually twisted the housing drag racing it. The center section twisted upward, messing up the pinion angle. I replaced it with a 12-bolt. Not as pretty, but plenty beefy.
Full disclosure: It was a stick shift with ladder bars - about as violent a setup as you could build back when.
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