What's the best way to correct my 65 fastback from drifting and going side ways on fast acceleration. I did the Granda disc. brake swap some time ago and I know the front end geometry changes, front end alignment helped. Also have new close ratio steering gear box installed. Will heavy duty sway bars help alot or not much? or what else can I do? Thanks..
Last edited by g017674; 07-05-2008 at 09:05 AM.
Reason: spelling
Well, How bad is it? My 289's all pulled a bit during hard "gitonits". I found out two things over the years that cause this.
First was weak or broken rear springs. If the butt end starts to squat as you take off, and one spring settles lower than the other, the rear axle tends to steer towards the weak spring. Not very much, but enough to notice. Stronger shocks may help, but new springs are needed. Traction bars are usually not much help either.
Second, front suspension. Springs, worn joints, bushings, all can cause this. Its reverse of the rear end as it comes from the front end raising up. It could be simple "bump steer" where the rising front tugs against the pitman arm and pulls the tie rod toward it. The front end pulls right in this case. There's not much you can do about that. I believe this is what 'andrewmp6' was refering to. This is normal. Watch the "Bullitt" movie if you want to see this in action! As far as the worn parts are concerned, anything that allows the static state of the suspension to shift can cause drifting. Those two big rubber things on the front cross member that locate and pad the strut rods can get worn and allow the control arms to drift rearward. Bad ball joints. Bad A frame or control arm bushings. Anything worn like this up front can let things get sloppy, yet when at rest can still allow an alignment tech to get the alignment right and insist everything is OK.
Of course, we haven't addressed tires yet, posi diff having worn out friction plates or needing lube additive causing too much slip in diff, crown of the road issues, bad or bent frame rails, use of shackles to jack rear end up, etc.
So you see, some research is needed here. If I had to choose the two most likely I'd suggest bump steer and rear springs as the source.
If you've replaced the front suspension and have had it aligned correctly, then the problem does lie in the rear suspension. One spring could be settling like 60's Refugee said, or the springs could be twisted.
Traction bars could help, but I think the best solution would be to go to a truck arm or torque arm setup. I don't know of any truck arm manufacturers for the Mustang, but Griggs Racing and Total Control Products both make torque arms for classic Mustangs. It's a very stable setup that will simply plant the rear wheels on take-off. The Griggs rear suspension, which I would personally reccomend, costs about $2,000 and will improve the rest of your car. If you want, you can just install the torque arm and that will cost about $750.
A sway bar may help a little bit by reducing weight transfer to the right wheel under hard acceleration. Instead, the wheels should have even traction and grip a little better. It's alot cheaper than the torque arm, but doesn't have as many benefits.
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Proud owner of a '65 289 coupe w/ C4. Equipped with Edelbrock Performer intake K&N air filter, and 600 cfm carb, Comp Cams Xtreme Energy valvetrain, Comp Cams XE262H cam, MSD ignition, and ported heads. Suspended by 600# 1" drop front and stock rear springs, KYB shocks, 1" front and 7/8" rear sway bars, and Traction Master style traction bars. Your friendly suspension kid.
i'm replying in reguards to the comment you left andrew.
well, first off, i don't know what QVC is, so your inside joke proves nothing more than the fact that you obviously watch it.
also, have fun googling pictures of mustangs you'll never have.
and don't go to forums if you have your tampon still stuck in your vagina, because there is something called a sense of humor that people have, other than yourself.
so please overdose on pro-activ, and don't try being an "asshole" anymore, because you suck at it, as well as how you suck at life.
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1967 Cougar, an original Hi-Po 289 with FoMoCo heads, Hedman headers, 3 inch H-pipe flowmasters, Titanium valves, Edelbrock 750 cfm, Mild cam, Ford 9 inch 4:11 posi trac. rear end, bored .30 over,High rise intake, Original black on black leather interior, original vinyl top and original mercury indian rims.
Try lowering the rear tire pressure, also a softer compound rear tire will help you go straight(move up a size to a larger contact patch also). The shelby traction bars will help . Do you have sub frame connectors??? The subframe connectors will prevent severe body twist that could lead to alingment changes. Check your tie rods, with the weight on the car they should be level with the ground(bump steer) there is kits to correct this.
I have the same problem and I have sub frame connectors, an Auburn limited slip diff., new 5 leaf rear springs, 620 lb new front coils, all new front suspension, 235/60-15 tires, new strut rod bushings, front 1 1/8" antisway bar and 3/4" rear bar, KYB shocks and a quick ratio steering box.
When I get on it, the car will drift to the right. There is no wheel hop. It will just drift, but not to the point where I loose control. I have the front control arms lowered with a negative wedge kit installed. The control arm drop gives me a bit of bump steer and my 5.0 engine is a torque monster. I kept separating the left motor mount until I ran a bolt through it to keep it together. This is on a 67 FB. I also have the Shelby Traction Master traction bars, which I haven't installed yet.
I think that the problem with the drift may be associated with the engine's torque and the bump steer. I've also noticed that the drift is more pronounced on a road with a crown. I'm hoping that the traction bars will help, but I don't think I'll eliminate the drift completely. A softer compound tire may help too.
I think that the drift is partly "The nature of the beast" as I also had a 67 coupe without as many mods with the same problem. I'm going to get a bump steer eliminator kit and install the traction bars to see what happens, but Ford small blocks are torquey by nature and all of the drift may not be eliminated on a street set up.
I have the same problem with my 65. things that have helped.
first obviously worn out parts must be replaced.
second the total control rack and pinion steering has been great at eliminating wondering.
I have a 3/4 inch rear sway bar
total control sub frame connectors.
after I installed my currie 9 inch I found that my shelby underride traction bars, which I just left in place were not quite loaded the same. I ended up modifying the plate to make them sit right. this has helped a lot. I have a question about this to put to other more knowledgeable people. I was thinking when I did this that I would like to cut the tube off of the bars and modify them with screw in rod ends like on a 4 link to give me some adjust ability. do you think this would work? if not why not? I do not understand all of the variables in designing a good rear suspension
despite all I have done though the car still tends to squat and head to the right a bit on real hard acceleration.
Yeah any rwd with a good amount of power with leaf springs will pull one way or the other.Even the big block mopars which had a extra leaf on the right side does it too.
65 Fastback drifting and going side ways? 
