Differential and Transmission upgrade - Page 2 - Chevelle Tech
Transmission & Driveline Transmissions and Differentials

 35Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #16 of 85 (permalink) Old Jul 25th, 19, 12:25 AM
Senior Tech Team
Freddie
 
Join Date: Feb 2000
Location: Central City, Ky.
Posts: 9,358
Re: Differential and Transmission upgrade

I wasn't clear on that. You listed 3.42 and 3.54 as gear ratio options for your rear end. Those gear ratios are not available for the 8.2 10 bolt, which is what I assumed you had because that is what would have been in that car. The correct gear ratios in that range for that rear end would be 3.36 and 3.55.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
big gear head is offline  
Sponsored Links
Advertisement
 
post #17 of 85 (permalink) Old Jul 25th, 19, 12:50 AM
Senior Tech Team
 
Join Date: Oct 1999
Location: Sin City
Posts: 4,918
Re: Differential and Transmission upgrade

Quote:
Originally Posted by jelco View Post
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.
big gear head likes this.

64 2 door Wagon Build thread

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


67 2 door Sedan LS1 T56

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Pete 67 is offline  
post #18 of 85 (permalink) Old Jul 25th, 19, 1:21 AM Thread Starter
Tech Team
 
Join Date: Jun 2019
Location: San Diego
Posts: 166
Re: Differential and Transmission upgrade

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?
jelco is offline  
 
post #19 of 85 (permalink) Old Jul 25th, 19, 8:56 AM
Gold Member
Gene
 
Join Date: Sep 2000
Location: Buffalo NY
Posts: 14,590
Re: Differential and Transmission upgrade

In the 10 bolt, yes.

Gene
ACES 3112/Team Chevelle Gold #62
Be big, be a 'builder'!
427L88 is offline  
post #20 of 85 (permalink) Old Jul 25th, 19, 9:10 AM
Gold Founding Member
 
Join Date: Aug 1998
Location: 30.1298228, -97.9771166
Posts: 6,518
Garage
Re: Differential and Transmission upgrade

Quote:
Originally Posted by jelco View Post
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.
71350SS, lucifershammer and Dansk like this.

Quote:
Originally Posted by Jordan Peterson
The motivation that drives the commission of the worst human atrocities is an inevitable social consequence of the refusal of the self conscience individual to make the sacrifices appropriate to establishing a harmonious life and their consequent degeneration into a kind of murderous and resentment filled rage propagating endlessly through its variations in society until everything comes to an end.
Alan F is offline  
post #21 of 85 (permalink) Old Jul 25th, 19, 9:50 AM
Senior Tech Team
Freddie
 
Join Date: Feb 2000
Location: Central City, Ky.
Posts: 9,358
Re: Differential and Transmission upgrade

I agree, the 3.55 would probably be best with overdrive. If you think that you may not go through with the overdrive installation then use the 3.36.
71350SS and 427L88 like this.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
big gear head is offline  
post #22 of 85 (permalink) Old Jul 25th, 19, 12:10 PM Thread Starter
Tech Team
 
Join Date: Jun 2019
Location: San Diego
Posts: 166
I called Quick Performance and they said 3.55 or 3.73 would be good with overdrive, 150rpm difference with the 3.73.
Would I get better gas mileage around town with the 3.55?
jelco is offline  
post #23 of 85 (permalink) Old Jul 25th, 19, 4:32 PM
Senior Tech Team
Freddie
 
Join Date: Feb 2000
Location: Central City, Ky.
Posts: 9,358
Re: Differential and Transmission upgrade

Post pictures on here when you get started on this and we will help you read the pattern and help with direction on which way to go. Ask questions and you will get answers.
71350SS likes this.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
big gear head is offline  
post #24 of 85 (permalink) Old Jul 25th, 19, 7:04 PM
Tech Team
Brad
 
Join Date: Apr 2004
Location: Redondo Beach
Posts: 110
Garage
Re: Differential and Transmission upgrade

I have the 700 (did the swap about 20 years ago) and it holds up great. That said, buy a built 200 and you will be way happier. Nobody was building the 200's when I did the swap, so I had to shorten the driveshaft and modify the crossmember. You don't have to do nearly as much to use a 200, as it is the same length as your old transmission. Another advantage of the 200 is the gap between first and second gears is not huge. the 700 has a 3.06 1st gear and 1.62 2nd gear, and the 200 has a 2.74 1st and 1.57 2nd.

Shifting from 1st to 2nd at 5,000 rpm, the 700 will drop to about 2,600 rpm and the 200 to 2,900. I definitely feel the bog when the car shifts from 1st to 2nd.

I also have a (non-posi) 12 bolt with 2.73 gears and it is a highway monster. 2,000 rpm at about 80 mph. I think low to mid 3 series gears would be perfect.

Brad Waller
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

'66 Corvette | 352/??? | 4-speed | Wilwood Brakes | 245/50/16
'67 Chevelle | ex-SS396 | 355/700R4 | F-Body Brakes | 275/40/17
Brad Waller is offline  
post #25 of 85 (permalink) Old Jul 25th, 19, 8:45 PM
 
Join Date: Jul 2019
Posts: 11
Re: Differential and Transmission upgrade

Really the only major gear ratio difference is first gear. The rest are so close as to make little if any difference.
miketx is offline  
post #26 of 85 (permalink) Old Jul 25th, 19, 9:48 PM
Senior Tech Team
Greg.
 
Join Date: Apr 2011
Location: Ottawa, On, Canada
Posts: 4,968
Garage
Re: Differential and Transmission upgrade

Here is my 2 cents
if there is a Rearend in the car now drive it like it is for now as a DAILY driver

Then get all the right parts to swich over assembled
eg.
1. the right 12 Bolt Posi with the Gear Ratio to fit/match up to the new Engine / Trany / you are going use
2. get the 3/4 speed Trany you can afford with the lest amount of work needed to install it into your car
..... TH400 if you also want to do some fast fun time at the Track & Cruzin that is almost Bullet Proof with a 3.08 to 3.31 Gear Ratios in the 12 Bolt
..... 2004R for a Daily Driver & Cruzer with 3.55 or 3.73 Gear Ratios in the 12 Bolt
..... 4L80 for a Daily Driver & Cruzer with 3.55 or 3.73 Gear Ratios in the 12 Bolt
3. the Engine you want with it ready to go
..... LS SBC for good Gas Mileage and plenty of HP
4. a new Shifter to make sure the Trany will shift great
..... I just put a B&M Pro Ratchet in my 67 and I love how it shifts my Newly Rebuilt TH400 with a Reverse VB
5. a new correct lenght HD Driveshaft with 1350 Ujoints

67 Chevelle Malibu SS Cdn
Born 283 / PG / A51
468/TH400 2,500 stall/ S60 3.70 Gs
Prev Best on M/T ET S/S #3454 street Tires/Dress 2018/05/20
60' = 1.664
1/8 = 7.532 et / 91 mph
1/4 = 11.814 et / 115 mph
NEW Best with 3,500+ Stall TC 2019/09/08
60' = 1.547
1/8 = 7.311 et / 91.76 mph
1/4 = 11.595 et / 114.28 mph


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Kirk's67SS is online now  
post #27 of 85 (permalink) Old Jul 29th, 19, 8:19 PM Thread Starter
Tech Team
 
Join Date: Jun 2019
Location: San Diego
Posts: 166
Re: Differential and Transmission upgrade

Quote:
Originally Posted by Kirk's67SS View Post
Here is my 2 cents
if there is a Rearend in the car now drive it like it is for now as a DAILY driver

Then get all the right parts to swich over assembled
eg.
1. the right 12 Bolt Posi with the Gear Ratio to fit/match up to the new Engine / Trany / you are going use
2. get the 3/4 speed Trany you can afford with the lest amount of work needed to install it into your car
..... TH400 if you also want to do some fast fun time at the Track & Cruzin that is almost Bullet Proof with a 3.08 to 3.31 Gear Ratios in the 12 Bolt
..... 2004R for a Daily Driver & Cruzer with 3.55 or 3.73 Gear Ratios in the 12 Bolt
..... 4L80 for a Daily Driver & Cruzer with 3.55 or 3.73 Gear Ratios in the 12 Bolt
3. the Engine you want with it ready to go
..... LS SBC for good Gas Mileage and plenty of HP
4. a new Shifter to make sure the Trany will shift great
..... I just put a B&M Pro Ratchet in my 67 and I love how it shifts my Newly Rebuilt TH400 with a Reverse VB
5. a new correct lenght HD Driveshaft with 1350 Ujoints
Yeah, probably wise to wait to upgrade the rear end until I have the tranny and engine to upgrade with it. I'm going to try to find a decent salvage yard LS motor at some point then buy a rebuilt 200 or 7004R transmission. If I'm not racing I'm thinking I can stick with the 10 bolt 8.2" for a while before upgrading to the 12 bolt 8.875".
jelco is offline  
post #28 of 85 (permalink) Old Jul 30th, 19, 2:05 PM
Senior Tech Team
Greg.
 
Join Date: Apr 2011
Location: Ottawa, On, Canada
Posts: 4,968
Garage
Re: Differential and Transmission upgrade

Quote:
Originally Posted by jelco View Post
Yeah, probably wise to wait to upgrade the rear end until I have the tranny and engine to upgrade with it. I'm going to try to find a decent salvage yard LS motor at some point then buy a rebuilt 200 or 7004R transmission. If I'm not racing I'm thinking I can stick with the 10 bolt 8.2" for a while before upgrading to the 12 bolt 8.875".
If you gave me a 7004R FREE I would not put it in my car

would sell it to someone else who wants the problems it will have
jelco likes this.

67 Chevelle Malibu SS Cdn
Born 283 / PG / A51
468/TH400 2,500 stall/ S60 3.70 Gs
Prev Best on M/T ET S/S #3454 street Tires/Dress 2018/05/20
60' = 1.664
1/8 = 7.532 et / 91 mph
1/4 = 11.814 et / 115 mph
NEW Best with 3,500+ Stall TC 2019/09/08
60' = 1.547
1/8 = 7.311 et / 91.76 mph
1/4 = 11.595 et / 114.28 mph


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Kirk's67SS is online now  
post #29 of 85 (permalink) Old Jul 30th, 19, 11:52 PM Thread Starter
Tech Team
 
Join Date: Jun 2019
Location: San Diego
Posts: 166
Re: Differential and Transmission upgrade

Were you racing it?
I'm looking for a 200R4 since it will be easier to install but I've heard parts are easier to come by for a 7004R.
I'm not interested in a floor shifter, I'm just going to keep the original steering wheel shift.
jelco is offline  
post #30 of 85 (permalink) Old Jul 31st, 19, 6:04 AM
Lifetime Premium Member
Eric
 
Join Date: May 2017
Location: Walden, NY
Posts: 682
Re: Differential and Transmission upgrade

Since you are in southern CA you could always go to bowtie overdrives for your 2004r. I think there are other shops down there as well. Be wise and have them build and install it. That way they own any issues. The 2004R can be finicky to get everything right. I think Bowtie has one of the best TV setups out there. Having said that, if I was planning an LS swap, I would also swap in a more modern transmission at the same time and forget about the 2004r or 700r4.
Kirk's67SS likes this.
Dansk is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address. Note, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in










Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome