[Ben-68Dart440]

About a month ago, I purchased a 1968 Barracuda Notchback, barely rolling chassis, everything else in pieces. The car has 4.5" lug pattern front and back. In front it has 11" rotors with slider caliper mounts which mount in front of the spindle. The part numbers on the caliper mounts are 77623258 on right side and 77723258 on left side. They both have pentastars cast into them, so we know it's a Chrysler set up. I do not have calipers and the previous owner bought the car from a paint shop where the car was left with an unpaid bill, so I have no way to ask whoever installed the brake system. We know they are not original, since they are 4.5" lug and slider caliper instead of the original 4" lug and 4 piston caliper. The question is what do I have and what calipers do I need? lol

 

[Jim_Lusk]

Without doublechecking my parts at home, I would say that you have either a 73-76 A-body setup or one from an Aspen/Volare/Fifth Ave./Diplomat/etc. The caliper I choose to use with those is the 76 A-body part. Around here the core is cheaper than the earlier big bolt A-body caliper. The holddown kit is also available.

 

[Ben-68Dart440]

Measurements

OK, when you get home, I checked the spindle/knuckle: I cannot find a part number, so the only casting number I have is from the caliper mounts 77723258/77623258. I did take some measurements
Steering Arm Bolts at Knuckle: 4 5/16" center to center
Caliper Mount Bolts at Knuckle: 3 1/8" center to center
Spindle Length: 5 1/2" from vertical base, flat portion of knuckle
Caliper slides: 4 1/2" from outside to outside of sliders for pads
I also tried to attach a picture. Thanks for your help.

 

[Ben-68Dart440]

Some more measurements

I was trying to figure out how to measure the height of the spindle/knuckle assembly, so here's what I got. If I hold a straight edge across the top of the knuckle where the upper ball joint goes thru, I get 7 1/16” vertical distance from center of both steering arm bolts to top of knuckle. I get 4 13/16” vertical distance from top of painted portion of spindle to top of knuckle. Also, for one more statistic, the width of polished spindle where inner wheel bearing rides on it is 1.375”

 

[Jim_Lusk]

The thing I didn't explain very well is that all of the slider calipers for spindles that will fit your car are completely interchangeable. There are different piston sizes and material, but they all physically bolt on. I have never had trouble getting the 76 A-body calipers, which is what I tend to choose whether I use the tall (Apsen/Volare/Etc.) or the short (A-body) spindle. They will attach to your spindles and function fine. I also tend to use a 73 A-body disc brake master cylinder. You can mix-n-match bore sizes of the master and calipers for optimum braking, but I've never bothered.

 

[Ben-68Dart440]

Torque Specs

tnku
I'll use the 76 calipers and 73 MC.
If you do happen to know what Steering knuckle/spindle set up I have, I am still interested in knowing.
Also, if these aren't the 73-76 A-Body knuckles, should I still use the 73-76 A-Body torque specs for the ball joints, steering arms, and control arms? If not, what should I use?
Finally, if I am going to use manual brakes, what combination valve should I use and where can I get it? Further, I saw an article where I believe Rick Ehrenberg of Mopar Action used a proportioning valve for the rear brakes, but no metering valve for the fronts on a 62 b-body. Has anyone tried manual brakes with no metering valve? Does it work OK or do you get nose dive?

 

[Jim_Lusk]

The adjustable prop valve is all that is needed. Nothing for the front, or use the factory combination valve found on late a-bodies. Both of my son's big block a-bodies have manual brakes with disc front and 11" drums out back. My 440/727 67 Barracuda convertible will also manual disc/drum, but with late model (80s Fifth Ave.) 10" rear drums.

 

[Ben-68Dart440]

Caliper Position

Here's another question: whatever my brake swap came from A, F, etc, should the spindle/knuckles always mount so that the calipers are forward of the control arms?

 

[Jim_Lusk]

It really doesn't matter. Early A-body disc brakes (Kelsey-Hayes four piston) mounted to the rear, late A-body (single piston slider caliper) mounted to the front. F/M/J (Aspen, etc.) mounted to the rear. The spindles are symetrical and can be swapped for sway bar clearance or any other reason. All that really matters is that the caliper is mounted so that the bleeder is UP.......

 

[Ben-68Dart440]

I got a 73-76 A-Body kit and mounted the spindles on my 68 Dart with the calipers to the rear of the control arms because the brake line fittings were to the rear of the control arms, It sounds like I mounted the spindles backward. But, you're saying this is not a problem to wheel alignment or handling?
Thanks, Ben

 

[Jim_Lusk]

Nope, not a problem.

 

[Ben-68Dart440]

Torsion Bars and Handling

My 68 Dart, not the Barracuda I originally started this thread on, but my 1968 Dart does have the A-Body set up with the calipers to the rear. It has 6-cylinder torsion bars, which I read somewhere that I ought to keep because of advantage in weight transfer when I finally get the Dart to the track. The Dart has 440/727 set up. It has always felt ungainly, clumsy going around normal turns while street driving. I had it aligned by a reliable shop whom I have dealt with for years. Since the spindle knuckle set up isn't causing the problem, do you think that the torsion bars are? If so, what size would you recommend for an intended street/strip car?

 

[Jim_Lusk]

It's the torsion bars and the lack of a sway bar. It could also be rear springs and shocks, too. I wouldn't drive a slant A-body that didn't have at least 340 torsion bars, rear springs, and front sway bar. You sacrifice very little at the track to have a car that has good street manners, in my opinion.

 

[Bill_Reilly]

You have 73-76 A-body spindles. You can tell by the little curved notch in the upright just above the dust shield face. The FJM spindles dont have that little notch.

 

[Ben-68Dart440]

It's the torsion bars and the lack of a sway bar. It could also be rear springs and shocks, too. I wouldn't drive a slant A-body that didn't have at least 340 torsion bars, rear springs, and front sway bar. You sacrifice very little at the track to have a car that has good street manners, in my opinion.

Who would you buy the sway bar from? Addco?
What would you buy?

 

[Jim_Lusk]

Addco is probably the last choice, but still will work. Lots of guys are favoring Hotchkis these days, but they are pricey. Hellwig makes nice sway bars, too. Mopar Performance, Firm Feel, or PST for torsion bars.

 

[Ben-68Dart440]

torsion bars

Just Suspension has a set of 1" bars for $200. The sales girl claims Moog made them in the USA. I can't find any torsion bars on Moog's website. Firm Feel sells 1" bars custom made in their shop for $320. Would you save the $120 and go with Just Suspension or put out the extra money for Firm Feel? Mopar Performance makes a .9", but I thought I'd go for 1" since the .9" is for a 383 and my Dart has a 440.