Hello A friend of mine has offered me a 57 chev diff to put in my 53 chev sedan. I currently have a HQ rear but it has a short gear ratio. The guy claims the 57 diff has a ratio in the 2.7 range. Does anyone know the with of the 57 diff in comparison to the 53? Will it match up to a HQ tailshaft? Will the spring mounts match stock 53 springs? Is this diff ratio realistic? What colour do smurfs turn when they choke? I know its a bunch of questions I just need to factor wether it is best to leave the diff I have in there. If there's anything else I should consider feel free to sing out. Thanks in advance.
Yeah, and 55-57 I think the highest is a 3.48 or so, the 3.08 was in 58 and later cars. 55-57 Chev rearends are supposed to be the best ones to put in 49-54 cars because the width is the same. Or it's damned close. Anyways they fit good and make an open drive conversion fairly simple. I believe you need to relocate the hole for the spring perch by a little bit for it to line up correctly (drill a new one in the right place). Oh, and they turn purple. Or so I've heard.
Is it hard to swap the ratios in the 57 diff? I know it is a fair bit of work to change a HQ diff ratio.
Swapping out the gears in a 55-64 diff is as easy as swapping the center section...... You just have to find the right center with the gear set you want. Or, you'll have to buy a set and have them set up ( or do it yourself) just like any other gear install.
When tri-5 rear ends were cheap and easy to get that was the normal swap on a 49/54 Chev car. You do have to drill a new hole for the spring bolt to go through to properly locate the rear end. I think the hole has to be 1-3/4 inch forward of the stock hole but a guy would have to measure the stock axle and pad to be sure. Measure the distance between the locating hole in the pad an the centerline of the axle housing. I'm not sure if the pads have to be moved or not on this swap.
i think when you choke em, they turn flesh color...really I too have heard that the 55-57 rear axle is a great candidate for a swap on the pre open drive line chevy cars..like 49's thru the 54. the width is either dead on or dam close enough. as far as the ratio's go, I dont know that to say. switching the ratio out shouldnt be too difficult.
the pads are wide by 1/4" and the locating hole needs to be drilled forward of the stocker. Wheel hop will be pronounced with stock springs.
Get Posies's springs they will bolt right up to your 57 rear and they will center the wheel in the fender well. I have a 52 chevy that I am currently working on and I bought the springs and I am putting a 56 rear end in my 52. You have to weld on the perches to adapt it though. Many other methods out there, but I read for hours and found this to be the easiest way to switch to a open drive line and lower the car or keep stock height at the same time.
The Posi unit I'm running (drain plug on the bottom-57 ?) is a 3:55. Testing it with a mark on the tire and counting the yoke as it spins...3 1/2 turns Is this right? Newer(80's) Camaro rears are 54" and come with a variety of gears and Posi capability.
I checked my Camaro rear by turning the yoke and seeing how many times to turn the drums once - got not quite 3 1/2 - works out to a 3.42 looking at the charts of available gears - but it's also out of the car. Actually an S10 2WD is 54" and way too narrow for a 49-54 Chevy - an 82-93 Camaro is 62" and a 70-81 Camaro is 61.5" - we've been going over this a lot on Chevytalk.org the last couple weeks. I think the S10 4x4 is 59" or 60" - guys using them have mentioned needing a half inch or so spacer on the wheels to make them fit right. From what I found, 55-57 you don't *have* to move the perches - drill your new hole like 1.5" forward and about 1/2" inward of the existing locating hole - and it will drop into place and just hang off the spring by a half inch. Guys have run them that way; I forget now what they said they did for the bottom plate. It might even be the other side lines up and there's no problem.
The 67-69 Camaro and 68-74 Nova rears are great for the early Chevys too. I put a 74 Nova one in my son's 57 for a better highway gear to get us up from the consistent 15MPG the car delivered.
I put a 55-early 56 rear in the wifes 54. I used the Posie setup-springs, shackles, u bolts, shock mount pads etc... worked slicker than snot on a door knob.
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