# Will any 12 bolt truck rear ends fit a 1970 Lemans with minimal alterations?



## Daykron (Oct 13, 2020)

I see a lot of rwd trucks that are being junked or parted out. 

Maybe a Ford 9" ? I watched a video on how to shorten one, but I don't know if I'd have to shorten it. Maybe make it longer?

I just don't know much about America Cars. 

Thanks


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## PontiacJim (Dec 29, 2012)

Daykron said:


> I see a lot of rwd trucks that are being junked or parted out.
> 
> Maybe a Ford 9" ? I watched a video on how to shorten one, but I don't know if I'd have to shorten it. Maybe make it longer?
> 
> ...


Most likely not. Don't most trucks use leaf springs, or has that changed? A-body cars use coil springs.

Your control arm and spring mount locations will be completely different and even pinion angles could be different. You can cut down a rear end, but not something the average guy would do or have the tools to do so.

It might be possible to get a bare aftermarket rear axle set-up to fit the A-body rear suspension and then swap the guts from a donor over to the bare housing. I used a Quick Performance Ford 9" axle housing set-up for an A-body ( 1968 Lemans) which included the axles (I got 31 spline axles, but I think stock on most 9" is 28), heavy duty wheel bearings, and got the heavier axle tubes. I also purchased the 11" drum brake kit, but you might be able to retro fit a disc brake set-up pulled from a junk yard. Then you need the front carrier complete from a Ford 9" that uses the same splined axles as the ones you have. That should for the most part be what you need. Never done this, so don't hold me to it word for word - just a possibilty that may work.

The 12-bolt would require more work as you have to set up the gears as they do not have a removeable third member/carrier.


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## 67ventwindow (Mar 3, 2020)

Not a Ford expert but the 28 spline is what I have in my 67 Cougar with 289. I have been told by the Ford guys its not a drag racing axle. While its an upgrade for a Ford going from 8" 28 spline to a 9" 28 spline cause the price is not great and you can still find them on Craigs list that are a quick swap. What the Ford guys say about the 28 spline is the same complaint about the BOP stock rear not a heavy-duty setup. The 31 spline is what built the reputation of the Ford 9.


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## Daykron (Oct 13, 2020)

PontiacJim said:


> Most likely not. Don't most trucks use leaf springs, or has that changed? A-body cars use coil springs.
> 
> Your control arm and spring mount locations will be completely different and even pinion angles could be different. You can cut down a rear end, but not something the average guy would do or have the tools to do so.
> 
> ...


 Thanks. I know it is 31 splines and I did watch a guy shorten a 9" and


PontiacJim said:


> Most likely not. Don't most trucks use leaf springs, or has that changed? A-body cars use coil springs.
> 
> Your control arm and spring mount locations will be completely different and even pinion angles could be different. You can cut down a rear end, but not something the average guy would do or have the tools to do so.
> 
> ...


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## 1968gto421 (Mar 28, 2014)

Any decisions yet on what you will do re: rear axle swapping? Is your LeMans a manual shift and this is motivating you to look for a stronger axle? Have you put in a 455 or other Pontiac V8 and had it modified for more power? If not your 8.2 may serve you well with a stock 350/400 especially with an auto trans.
Most truck rears are going to be wider as trucks (except compact/mini) are wider to carry a load. Also a truck rear is generally much heavier than a passsenger car rear creating alot of unsprung weight messing with your handling and ride. Just sayin'


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## Daykron (Oct 13, 2020)

1968gto421 said:


> Any decisions yet on what you will do re: rear axle swapping? Is your LeMans a manual shift and this is motivating you to look for a stronger axle? Have you put in a 455 or other Pontiac V8 and had it modified for more power? If not your 8.2 may serve you well with a stock 350/400 especially with an auto trans.
> Most truck rears are going to be wider as trucks (except compact/mini) are wider to carry a load. Also a truck rear is generally much heavier than a passsenger car rear creating alot of unsprung weight messing with your handling and ride. Just sayin'




No, I was just thinking about the future. My 70 Lemans is all original with 350-2, th350, bop 8.2.

I was just hoping I could make it a little more than what it is, with in my budget.

My car isn't extremely powerful and I've never burnt rubber. 


Daykron said:


> Thanks. I know it is 31 splines and I did watch a guy shorten a 9" and


Thanks for your advice and valuable information. I need to learn more about my car and about older cars. 

It's tough trying to learn by videos and reading. This makes the info that you give me so much more valuable to me. Since it is straight forward and is answering my questions.

Thanks again for spreading your knowledge
. I need to buy some books


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