Rear end question

timwhite · Post by **timwhite** » Sat Feb 15, 2003 9:52 pm

Hi every one. I'm Tim from Cleveland OH. I have a 67 i want to rally race, but the differential is shot. I want something strong, but i don't really want to use a ford because of weight. D

oes anyone know if there is a later model rear end i can swap for my roadster?
Maybe from a light truck?

Post by **S Allen** » Sun Feb 16, 2003 12:14 pm

Tim,

Welcome and thanks for registering. I did some searching and there were two rear ends that have been used in engine swaps in roadsters. Actually one that is proven to work. One guy is doing a rotory conversion and he is going to use a 510 IRS-not proven to work as yet! There have been several successful installations of Ford rear ends. They do not just bolt up and go as the rear end has to be shortened to fit into the roadsters frame. Not a cheap prospect unless you have a buddy working in a rear end shop.

I would try to locate a used roadster rear end which would prove to be much cheaper. Good luck!

Steve

DELETED · Post by **DELETED** » Sun Feb 16, 2003 1:38 pm

DELETED

Post by **S Allen** » Sun Feb 16, 2003 2:00 pm

Mark,

Interesting! What about the bolt pattern on the Mazda rear end? Are they the same as the roadster? Just curious.

Steve

timwhite · Post by **timwhite** » Sun Feb 16, 2003 2:36 pm

The SE?
That's interesting... how much does it have to be shortened?
And yes i'm almost sure the bolt patern is different.

timwhite · Post by **timwhite** » Sat Feb 22, 2003 2:30 pm

hey, i looked around and the Mazda IS the same bolt pattern as the datsun so i can use the rear and the aluminum rims to boot, but will this put me into a modified racing class?
either way i'll probably miss this season anyway. i'll be ready for next years.... ha ha ha.
vroom. cheers to the best forum yet!

Post by **S Allen** » Sat Feb 22, 2003 2:45 pm

Hey Tim,

Thanks for the update. That is good info. Did anyone ever reply to how much if any it needs to be shortened to fit the roadster frame?

Steve

timwhite · Post by **timwhite** » Sat Feb 22, 2003 10:04 pm

Sorry no word yet on how much it should be shortened...
but as i figure it if the rx7 wheels fit, late 80's mustangs should go too. not sure on backspacing, don't have alot of experience there.
I'm gonna have a go at it sooner or later with the rear and i'll let post what i find.
stay tuned...
Tim

Ivin · Post by **Ivin** » Sun Feb 23, 2003 10:40 pm

Hi-

Since I am a novice........ When you refer to shortening the rear end, what does that actually mean? Is it shortening the drive shaft or the actual axle? Also, I assume that this would allow one to use disc brakes in the rear. Is it a solid axle suspension or is it independent suspension?

Please keep us posted. I may want to do the same thing one day. Could you also list the name of the person or place that did this modification in Maryland. I am in NC, and if I ever decided to go that route, it would be worth the drive.

Thanks,

Ivin

TR · Post by TR » Mon Feb 24, 2003 2:29 am

Hey all, this is very interesting indeed...It may be possible to upgrade the entire rear end (with a bit of work) and get an LSD and disc brakes for about the same as the hard to find LSD's cost. I imagine the Mazda design would be lightweight, too-Not big and bulky like a mustang, etc.

According to this site, the track of the Mazda is 55.1 in.

www.geocities.com/MotorCity/Speedway/3734/firstgen.html

The track on a roadster (from R&T) is 47.1 in.

So, you will need to remove some length from each side of the axle...

Also, the site says that the final drive ratio is 4.076:1 for the GSL-SE and 3.9:1 for the non GSL-SE.

Hmmm...TR

timwhite · Post by **timwhite** » Mon Feb 24, 2003 11:59 am

Ivin-

It's funny that you showed up because due to my lack of garage space, my roadster is in NC. Rockingham to be exact.

Four inches is a little more that i thought would have to be removed from each side, but in this case it's ok because we already have an rx7. the rotary is kapoot, but the car is fine besides...
i could even use the seats i think...
ah yes, dreaming is great because it's free...

Post by **spl310** » Mon Feb 24, 2003 4:46 pm

You have to take into account the offset of the wheels to determine exactly how much has to be removed. You can measure the overall axle widths to get the accurate amount. If you are planning custom wheels, this is a great time to optimize the width based on the wheels.

Just my .02 from the peanut gallery....

Sid

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