Does anyone know how strong a 57 Chevy rearend is? Im going to be running about 400-450HP, will it hold up? Its not the posi center from a vette, but will that may be something ill have to look into?
How come people used to replace them with Pontiac & Olds rear ends and with Dana's & 9 inch Fords today?
Never known as a strong rear. I probably busted 25 of them in my 4-speed cars, in the '60s. The posi, and a set of race axles would help, but I would just swap it out.
Not strong at all man!! I have blown up so many of those in my Model "A", that I lost count. You should find a stronger rear-end for that application. Jimmy White
My dad say's he swears that Laura Scudders made that rearend because they're made out of pressed potato chips. I had a 56 nomad with a 550hp 406 & Turbo 400 with 4.56 in a"P"case. The axle tubes starting collapsing over the spring purches. This was with spring clamps to control wheel hop and using M & H 275/60 "stickies". The Nomad did weigh 3950lbs. Buy a Dana 60 from Strange Engineering. You can get the whole assembly with all the goodies for what a 9" third member will cost, and contrary to popular belief they are only 60 lbs. heavier than an 83/4.
They are generally good to 300hp. A little more if the car doesn't get any traction. Posi wasn't just used in the 'vettes...
I tore up the one in my 56 wagon.I'm running about the same hp and a m22 4 speed.I put a 10 bolt posi with 4:88's under it.It came out of a 67 442.My Dad has a 67 442 with a 10 bolt posi and it's been in the car since new and he hasn't been nice to it and never had a problem.That motor is pushing over 400 hp and is also a 4 speed.They are readily available and alot cheaper.If you are using it in a 55-57 you will get some more clearance.
Same results here. 55 chevy, 389 pontiac, 4 speed hydro, headers, 7" recap cheaters, ran 14.0 at 96. Blew the spiders constantly. Never could afford a posi but this car always spun both wheels unless you were on a tar road. Boneyard rears were $10 if you removed them or $15 if they removed it.
I race a1956 Belair Currently mine is set up with a 488 posi. This unit has been in the car for the past 6yrs. without any problems. I run goodyear 29x9x15 drag slicks. Small block chevy, 500 plus hp. Last weekend it turned 12.67's on an 18 year old engine build. The key to saving the rearend is skip the dry hops, it will break every time. As for a one legger, they will break. Hope this helps!!!
Here's an option for you if swapping isn't possible: http://www.bruneauperformance.ca/intro.html Look under "Our products for 409 cars" and you'll see a page for rear axle upgrades...mild to $$.
I've been running a 4.11 posi '57 in my 2200lb roadster for about 15 years now. Car runs 11.30s and hooks hard. No problems. They don't like a bunch of weight if you hook up good. A little wheel spin will help them last in a full body car. It would help if you said what kind of a car it was going in. Mutt
if you beef them up they are fine, those rears are prone to break on the rear main cap. honest charlie and alot of the old time speed shops used to sell a "main cap stiffiner" (girdle) kinda like the one speedway sells for beefing up the flat head 8 mains . I just had my rear guy weld a curved steel plate across the back of the right rear main cap (fitted to the curve of the cap). I also have stock GM gears with olds axels (from mosers), this is all in my restored dragster, that rear has over 200 1/4 mile clutch dumping tire smoking runs on it and has never been apar since I restored the rail in 1990. the one thing I will add is my rai only weighs 1300 lbs un-like a 3000 lb + car. * I added a rear saftey sheild on the back side of the rear after I took the one pic if you want to run that rear, put after market gears in it, after market axels and beef up the main caps