# rear end swap



## 65gto (Aug 2, 2013)

Planning on swapping out my rear end for something a little smaller. 3:23 or in that range. I'll need to find someone to do it for me. Wondering what parts I need to get. Ring & Pinion, gaskets, etc. Anything else? I'm going to verify what I have in first, of course. Supposed to be the original. Any idea on what this will cost? ballpark?


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## geeteeohguy (Feb 2, 2008)

What do you have now? No way to even ballpark without that info.


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## 65gto (Aug 2, 2013)

It's a 3:55, maybe bigger. According to the guy that built it 10 years ago, it's a stock posi. I will have whoever does the work verify it, before I buy any parts.


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## bobby326 (Dec 13, 2009)

If you have a 355 rear gear it not worth going to a 3.23. You will only drop about 2-300 rpms and the cost to change gears will b about $500. A better and easyer way to go would eighter be put on a taller tire 27/28" and that will drop your rpms or find another rear with 3.26 or 3.08 gear already in. Any 64-72 rear will work. 67-72 will b one inch wider but if your not running wide tire it will not be a problem. You can find a rear on craigs or swap meet for around $2-300. Will take about an hour to swap and you stillhave original rear if ever want to put back in. I did that wih my65. Had posi 3.73 gears so i bougt a 67 rear with 3.36 gears for $200. Quick clean and spray can paint and might as well put in new brakes.


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## ALKYGTO (Mar 29, 2010)

^ Agreed you will not see much difference. Here is Wallace Racings RPM calculator to find your ideal gear and tire size -

Calculate GEAR, RPM, MPH, TIRE DIAMETER

Pop in the cruising speed and rpm with your tire size and you can find the ratio you want.

Once you do you might want to consider an overdrive transmission in your future. That will give you that grunt and performance of a "low" gear and the economy of a highway gear.


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## 65gto (Aug 2, 2013)

Thanks all, I was looking at it today while I was getting an oil change. It's a 12 bolt, which makes me believe it's a chevy and not a Pontiac?.... Also, where do I find that 5 speed tranny?


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## ALKYGTO (Mar 29, 2010)

Here ya go..... http://www.summitracing.com/parts/a...l-fEEpPmJTA8sEYB3Ezfp9C6Zbe8wGOs4vBoCZ0bw_wcB

http://americanpowertrain.com/c-1102248-transmission-kits-gm-a-body-5-speed.html

Also you will need to do some minor floor pan modifications (had to cut the tunnel and raise it, invisible with carpet in the car) and a 26 spline clutch disc. Weekend install for one guy, preferably two. I also had to shorten my driveshaft a couple inches which a local shop should be able to do for you and you will also need a different front yoke for the driveshaft.. They have one available with a mechanical speedometer output. I was able to use my stock crossmember although I have a bolt in fabricated one now.

My favorite mod....and I've got a blower. I included the above links merely as examples and you may find one cheaper or a more or less complete setup.

Expect to invest $3000+ so changing gears is way cheaper. But with the 5 speed you get to keep that legendary GTO quickness while being able to cruise with modern cars on the highway. At 2500 rpm at 70+ mph they are usually getting out of my way!


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## 65gto (Aug 2, 2013)

Alky did you do the American power train or the one from Summit? It looks like the power train is much cheaper and includes the major parts. Does anyone else have experience with these?


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## ALKYGTO (Mar 29, 2010)

I bought my "kit" from Keisler (no longer in business) and it included the trans, shifter and the sheet metal required to raise the tunnel. I am sure for that price that the American Powertrain kit does not include the transmission.

When I installed my TKO I kept my steel bell housing and used a new McLeod clutch/pressure plate and new TO bearing and shortened the driveshaft myself (it is an aftermarket chrome moly unit) I went to Strange Engineering for the new billet yoke I used.

I would certainly shop around these were fairly new when I installed mine and there are lots more vendors for them now. I believe Summit or Jegs has a low price guarantee too but may not have a comprehensive kit available.

Here is another source, they have kits too that include the trans price..... http://shiftsst.com/store/essentials-kits/33-products/175-tko-essentials-kit


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## 65gto (Aug 2, 2013)

Thanks for your help on this. I'm now leaning in the direction of the 5 speed rather than the rear end.


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## ALKYGTO (Mar 29, 2010)

Cool! Any questions you may have I'll try and answer. I can think of at least five other members on here that have the TKO. I've heard only one complaint and that is breaking the third gear clutch fork on cars over 600 hp when powershifting. I make about 300+ more than that and I don't powershift but I do run wide sticky tires and have yet to hurt it. 


I have always loved the look of the '65 GTO, got any pictures to share? Did you know about the "garage" feature on this site? It allows members to view images and a description of your car by opening your "garage" under your avatar. 

I wish more members would use it! :smash:

Click here to start your own garage- http://www.gtoforum.com/mygarage/add


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## 65gto (Aug 2, 2013)

Shouldn't be a problem with my stock 330hp. I looked a little closer at that site, and it doesn't include the tranny. Total cost would be around $3500. I have about a million pictures. I'll work on getting some downloaded. 

Thanks again


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## 65gto (Aug 2, 2013)

https://lh6.googleusercontent.com/-...Fc50/w1133-h637-no/IMG_20150426_104417757.jpg

hope this works


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