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Discussion Starter #1 (Edited)
I have a 64 El Camino 283 engine, power glide transmission, with what I believe is the original 10 bolt 8” rear end and I believe it has a 2.56 gear ratio, GM1, #3839390N.

I’m thinking of upgrading to 3.42 or 3.54 gear ratio and upgrading to a 700 or 200-4R transmission in the near future. The plan is to make it a daily driver on street/highway and drop in an LS1 engine at a later date.
I have 17 inch wheels, 245-45-17 I believe.

I’m a noob but I plan to upgrade the gears myself. What’s a good upgrade kit?
Would this combination be ok for now with the 283?
Would the jump from 2.56 to 3.54 be hard on the 283 with power glide?
I’ve read the 200-4R is an easier install then the 700R4.
Any corrections, suggestions or advice?
 

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Your '64 will have the 8.2 10 bolt. The gear ratios for that rear end would be 3.36 or 3.55. Swapping gears is not an easy job for a beginner. You need a few special tools and you need to be able to set the pinion depth, bearing preload and backlash to get the correct contact pattern. The '64 8.2 had slightly different splines on the axles than the later years, so when you swap the differential for a 3 series you will also need to upgrade the axles. You will have to swap the differential for this gear swap because you currently have a 2 series and you need a 3 series for the gear ratios that you are considering.
 

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Discussion Starter #3
Thanks for the reply. The previous owner installed a 1979 Buick regal rear end to allow his wheels to fit. I may be doing things backwards but I think there's a little play in the gears and want the wider wheel base, since its off the car I figured I'd give it a shot. I'm a noob but I'll have a little help (hopefully).

I agree about the 2 (2.73 and 3.08 gearsets) and 3 (3.23 and 3.42 gearsets) series from the factory but I've also read if a 2 series carrier is used, a 'thick' ring gear set can be used for 3.42,3.73,or 4.10.
Is that not right?

I'll double check on the numbers and send a pic. I think 3.36 or 3.55 gear ratios would be fine for daily driving but would you recommend 3 series 3.42 gear ratio?
Any idea what kit would be good to purchase?
What Axles?
 

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If you have a 7.5 rear end from a '79 Regal then you need to get that out of the car now and put something in it that can handle a little power. That little rear end will not handle what you are building. Don't invest one dime in that rear end. Find a good 8.2 core from a '65 or '66 Chevelle and use that, or find a 12 bolt if you can.

You will have as much help as you need here.
 

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Where are you located? I'll be pulling out the stock 8.2 10 bolt from my '64 wagon in the next few weeks. I'll let you have it for a case of good beer. :D
 

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Discussion Starter #6
That's kind of you but I have an 8.2" 10 bolt already that I'm thinking about rebuilding. What are you replacing it with? I'm in San Diego.
I was told Astro Van's have an 8.8" rearend but I'm not sure about the wheel base difference. Anybody do an astro van swap?
 

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You need a '64 to '67 A body rear end. No other rear ends have the correct suspension geometry to work correctly in your car. You can install a G body rear end with special modified control arms and cutting and welding, but then you have a piece of crap 7.5 rear end that will not handle any power. My advice is keep it simple and use a rear end that will fit your car correctly.

The Astro van had the same 7.5 rear end as the G body. I wouldn't even consider it.
 

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That's kind of you but I have an 8.2" 10 bolt already that I'm thinking about rebuilding. What are you replacing it with? I'm in San Diego.
I was told Astro Van's have an 8.8" rearend but I'm not sure about the wheel base difference. Anybody do an astro van swap?
I found a 4:10 12 bolt posi from a '65 in Phoenix about a year after I bought my wagon. The owner had it on CL for $1200, so I jumped in my truck the second I saw it listed. Paid $1000 for it. Needless to say, I was pretty happy that afternoon.
 

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I found a 4:10 12 bolt posi from a '65 in Phoenix about a year after I bought my wagon. The owner had it on CL for $1200, so I jumped in my truck the second I saw it listed. Paid $1000 for it. Needless to say, I was pretty happy that afternoon.

Make sure it's a 12 bolt posi...
Bought a Chevelle with it said, 12 bolt posi........but it was an open one when we opened the rear end...
So installed a Detroit TruTrak Limited slip...Just a great addition...Hindsite, glad I had to upgrade...3.42 stock gearing...
 

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Make sure it's a 12 bolt posi...
Bought a Chevelle with it said, 12 bolt posi........but it was an open one when we opened the rear end...
Some people who don’t know much about cars use a description like “12 bolt posi” As if the terms are inseparable. Many years go it was that way with a Muncie. They were all advertised as “Muncie Close Ratios”. It sounded quicker.:wink2:
 

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Make sure it's a 12 bolt posi...
Bought a Chevelle with it said, 12 bolt posi........but it was an open one when we opened the rear end...
So installed a Detroit TruTrak Limited slip...Just a great addition...Hindsite, glad I had to upgrade...3.42 stock gearing...

I've been down that road many times. Every tweaker in the southwest thinks they have a 12 bolt posi rear. Whether its a 10 bolt, a 9 inch, a Olds 12 bolt or a lawnmower.

Some clown here in Vegas once advertised on the local CL that he had both a 10 & 12 bolt posi for a Chevelle. I get to his house after days of going back & forth, and him blowing me off a few times. When I show up, the first thing I see is the 12 bolt is a leaf spring rear, probably from a truck. Then I pull the cover off the 10 bolt & it's an open rear. At least it was from an A body. :rolleyes:

As I'm walking back to my truck, the idiot says "it's a posi man, it's just missing the clutches". Right....
 

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I don't see much difference installing a 700 vs a 2004r. Neither one left stock will take a whole lot of abuse.
The 200 has better gear ratios and fits the car without having to make as many modifications to the cross member and drive shaft.
 

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Discussion Starter #14
How does ‘big gear head’ know my GM1 rear end originally came with a 3.36 or 3.55 gear ratio?
Searching online showed “GM1” stamper rear end is 2.56.
What is a good 10 bolt 8.2” kit to purchase for a daily driver?
I’ve watched several YouTube videos but if anyone knows of a good one that is more specific to my car, please don’t hesitate.
 

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Discussion Starter #15
And I’m probably going to have to pay someone to come look at it to see if it’s in decent shape. If it is I may not bother messing with it right now.
Or get the fancy tools to do it right with the back lash and what not.
 

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How does ‘big gear head’ know my GM1 rear end originally came with a 3.36 or 3.55 gear ratio?
Searching online showed “GM1” stamper rear end is 2.56.
What is a good 10 bolt 8.2” kit to purchase for a daily driver?
I’ve watched several YouTube videos but if anyone knows of a good one that is more specific to my car, please don’t hesitate.

Freddie, aka Big Gear Head, is our resident expert on rear ends. He was simply letting you know that 3.36 & 3.55 gears are your choices when it comes to 8.2 10 bolts if you wanted to lose your 2.56 gears

3.23 & 3.42 are ratios for GM 8.5 10 bolts. Neither will work for your application.
 

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Discussion Starter #18
Ok thanks for the clarification. So get 3.36 or 3.55 3 series and replace the axles?

Several sites indicate a "GM1" has a 2.59 gear ratio (I mistyped 2.56 earlier), I haven't determined by counting the ring and pinion gears if it has been left that way over the past 55 years.

Do I have y'all's blessing to go ahead with 3.36 or 3.55 gear ratio if I leave the engine and tranny stock for a few months then switch to 200-4R or 700R4 and a salvaged LS1 down the road?
 

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Do I have y'all's blessing to go ahead with 3.36 or 3.55 gear ratio if I leave the engine and tranny stock for a few months then switch to 200-4R or 700R4 and a salvaged LS1 down the road?
If you are going to an overdrive transmission, do yourself a favor and go with the 3.55’s. With a low horse engine and low cruise rpm the car could be a little balky with the other gear.
 
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