Rear Sway Bar Questions!!!! Advice Needed

[promoguz 10]

I've had my 69 mach 1 in the shop for over a year. finally in the home stretch of things. And one area I've had problems with are SWAY BARS...

 

Took me forever to get a front sway bar to fit my 390 big block. Thats out of the way, But I'm also having problems with rear sway bars.

 

Purchased the Hellwig rear sway bar. nice looking bar, but wouldn't clear the bell housing and would have mounted on the curve of my frame rails. Long story short.. wasn't working! returned it. Just doesn't fit.

 

Now I tried the Addco sway bar, but returned it as well because it wasn't mounting right either due to exhaust interferrence issues or intereferrence with with Traction bars that came with the car when I purchased it.

 

Now i've eliminated the traction bars, redid the exhaust (dual Magna Flow 2.5) and I'm ready to insert a rear sway bar. well, at least try again!

 

What do you guys recommend. I keep hearing about mustang Plus' Grab a trak, but they look just like the Addco ones. Any difference? what other type of Rear Sway bars would you recommend I look into?

 

I'm looking at 3/4 to 7/8

 

Also, I keep seeing that some sway bars are for mustangs that originally came with a rear Sway bar. For Example ADDCO makes a sway bar for mustangs with Factory installed bars, but require some of the original hardware.

 

How much different are those sway bars for addco's other sway bars that come with all mounting hardware included? are the bends and shape that much different? Better? Worse?

 

I know I'm throughing out a bunch of questions but i just want to get an idea of whats out there, and what would work best for my application. I only use the car for street use.. no track or drag.

 

Also, one more thing. the Helwig mounted more on the rear dif/axle compared to the design of Addco's that seems to mount more onto the frame? Any advantages? disadvantages?

 

Thanks for you insight! I've been surfing up and down the web for info, but would love some opions from other owners out there who have revamped their suspension.

 

Jaime

[Solo2 0]

Try this site and ask how this adjustable rear sway bar can help with you application. Many, many great reviews with the race crowd on this bar.

http://www.swaybar.com/

[9R03F 10]

Might try rounding up everything from a `70 BOSS 302 rear sway bar set up. It's a 5/8" sway bar. The holes for the brkts to the frame are probably already in your car, or would be easy to do. You'd need the extra plates at the shock mounts and end links. I think that's it....

[70Mach03 12]

I had a 1970 Mustang fastback years ago that came without a rear bar. It was a 302-2V with the standard suspension. I added a 15/16†front bar off a big block Mustang and it really helped the cars handling. So I added an Addco ¾†bar to the rear. It was a bolt on type and I had to drill holes to mount the brackets. I never was really satisfied with the add on rear bar and couldn’t actually tell any difference. However my present 1970 Mach 1 came with the handling package which included the 5/8†rear sway bar. The factory bar was rusted and pitted pretty bad so I decided to upgrade it to a .875†bar and ordered one from a Mustang vendor. I took the old one off when the new one arrived but discovered they had sent me the wrong bar. They sent the add on bar like I had had years ago instead of the bigger stock replacement type. I sent it back but drove the car for about two weeks without the factory rear sway bar. I was surprised how loose the backend felt without any rear swaybar and couldn’t wait to get the other bar and put it back on (LOL).

 

I guess what I’m trying to say is the rear sway bar is a good mod but only if you can get the factory set up type that uses the bottom of the shock absorber plates. The non-stock bar that I had to drill holes in the frame and add on didn’t have much if any effect. I now have a 1.125†front bar and .875†rear bar on my Mach and am very satisfied.

 

One thing to consider when adding bigger sway bars is that now days cars come with big bars but soft springs. Years ago they used small or no bars but very stiff springs.

[02Lightning 10]

No, The sway bar connects one side of the suspension to the other side of the suspension to make your car stay flat around corners. Making your car tires spin at the same time has nothing to do with the suspension. For that you would need a traction loc unit inside the rear end housing, this locks the two rear tires together with clutch packs so they will spin together.

http://auto.howstuffworks.com/differential4.htm

[70Machboy 10]

Hey I'd sure like to know what bar you eventually put on the rear of your 70 Mach! I too have a larger than factory FRONT bar on my 70 Mach and am looking for a 3/4" REAR bar that MOUNTS THE SAME AS THE FACTORY bar did. My current bar is the factory 1/2" bar that just doesn't balance out my 1-1/8" front bar. However, I can't find any manufacturer that makes a FACTORY MOUNT 3/4" rear sway bar for the 1970 Mach 1. Can you help me?

- Gary - Please reply to me at: boeingboy@yahoo.com

[Unkleen 11]

Aldridge Motorsports in Portland, OR sells repro kits of the rear factory bars for Boss cars. Not sure what price though, but may be worth a call?

 

http://www.aldridgemotorsportsinc.com/pages/swaybars70.html

[Alan_Mac 48]

I have an Addco rear sway bar (.875 dia?) matched with a cobra automotive 1.250 dia hollow tube front sway bar. The Addco bar mounts under the axle tubes and the ends mount to the rear frame rail. I had Addco modify their rear sway bar by angling the center jog ~ 20-30 degrees down so it wouldn't hit my rear axle housing when going over a bump. My car tracks great with this combo.

[Cayenne06 10]

I have a 69 Mach 1 and wanted to improve it's handling. It too is just for street use. I contacted John at Open Tracker and he put together a front and rear package which improved steering and handling as well as lowered the car 1" all around. John recommended leaving off the rear sway bar for now because if you are not an experienced track driver it can make the car a handfull when pushed to it's limits. His advice was if you are not going to push the car (and on public roads you shouldn't) then skip the rear sway bar. If you have track experience and want to use the car on the track then a rear sway bar "sometimes" can be an improvement.

[Alan_Mac 48]

Aldridge Motorsports in Portland, OR sells repro kits of the rear factory bars for Boss cars. Not sure what price though, but may be worth a call?

 

http://www.aldridgemotorsportsinc.com/pages/swaybars70.html

 

The boss 429 rear sway bar is sweet. I would have used it I would hove know about it ~8years ago. Regarding opentrackers direction to not use a rear sway bar on the street. I totally disagree. Why did ford start using them on their performance cars?

[buening 63]

Rear sway bars increase oversteer. If you have wider tires in the back compared to the front, then you just further increased the oversteer by adding the rear bar. The bars used in the rear are, in stock form, pretty thin and you likely won't notice it on the street. Typically under/oversteer is only noticeable on the track when you are approaching the limits of traction through the corners. My opinion is unless you are doing a factory concours resto, leave the rear sway bar off as it is an unneeded expense for something you really won't notice is there. If you insist on the rear bar, make sure it is matched to your larger front bar and the springs are stiffer than stock. A 3/4" rear bar and a 1" front bar will not result in neutral handling. Remember it all works as a system, and balance is key :)

 

Handy tidbits to understand the effects of under/oversteer:

 

ADJUSTMENT ....................... TO INCREASE UNDERSTEER................................... TO INCREASE OVERSTEER

 

 

Front Anti-roll Bar .................. Increase bar diameter ........................................... Decrease bar diameter

Rear Anti-roll Bar ................... Decrease bar diameter ...........................................Increas e bar diameter

Weight Distribution ................. Move weight forward ............................................. Move weight rearward

Front Springs ............................ Stiffer .................................................. ................... Softer

Rear Springs ............................ Softer .................................................. .................... Stiffer

Front Wheel Camber ............... More positive .................................................. ...... More negative

Rear Wheel Camber ................ More negative .................................................. .... More positive

Front Caster ............................ More positive .................................................. ....... More negative

Front Tire Pressure ................. Decrease .................................................. .............. Increase

Rear Tire Pressure ................. Increase .................................................. ................ Decrease

[Jimjific 23]

I agree with 70 Mach03. I had a 70 Mach with the stock style rear sway bar and it was the most balanced car I had. I put an aftermarket (Can't remember what brand) rear bar on a 67 cougar I owned and it was terrible. I ended up taking it off and selling it. My advice is, if you are going to put one on go with a stock style setup.

 

Jim

[Alan_Mac 48]

Bruenings post is right on. My modded suspension and sway bars work well together as a system.

[LoneWolf2U 136]

:yawn:.... Oversteer....Understeer...... Better throttle control and you don't worry about it.:yes:

 

I run an 1 /18 front bar with an over the rear 7/8 bar on the BFG street tires.

Handles like a fast go kart and hangs ten on the on ramps.:cool:

I like the rear bar keeping the body roll in the rear down to a minimum.

Drivers choice on to bar or not.....

[RPM 1,190]

Every early Mustang I've driven had tons off understeer, and none had a rear sway bar. Accelerating during understeer does reduce the understeer. I plan on adding a rear sway bar of at least 3/4". The fastest cars I've raced against all had a bit of overseer.

 

Bob

[RPM 1,190]

Every early Mustang I've driven had tons off understeer, and none had a rear sway bar. Accelerating during understeer does reduce the understeer. I plan on adding a rear sway bar of at least 3/4". The fastest cars I've raced against all had a bit of overseer.

 

Bob