Bigger brakes, more suspension.

[Revhendo]

Okay, parking lot Zamboni fans. I am doing a '73 Roadrunner for cone killing duties. So, of course I am dropping a 440/4 speed combo in it. I've upped the brakes to the cop rotors on the nose and 11x2.5 drums in the back. I am going to box the lower arms. I have solid bushings to replace the Iso's on the K-frame. It looks like Firm-Feel is the choice for the sway bar on the nose.

My question is actually about the T-bars and the rear springs.
Are the front torsion bars the same as the 71 and 72 B cars?
Are the rear springs the same also? The ones I have are of the oval spring eye variety. I had heard that you could put bolts in the holes in those bushings (it's what they did on the police cars).

Cudazappa has been a big source of help on this to me. I want to hear your ideas or see what has worked for you folks out there.

So, let's hear it kids.

Rev.

 

[69 Runner]

I'm sure someone here has built a B body for autoX before, and can be a help. I've done that, but not with American cars so I'm not much help. I can tell you that 71-74 B bodies were pretty much all the same. I can also tell you to lighten everything as much as you can (within the rules) and strengthen all your suspension points. I've cracked sway bar mounting points and even sheered off a balljoint in a turn once. So beef it all up.

 

[Revhendo]

Absolutely, more beef than Wendy's.

Rev.

 

[kazer]

I would think a small block would be better for autocross, I don't see how you could use the torque of a big block in a parking lot. Hell, the 305 in my Camaro is almost too much, I spin on everything but the longest straights.

 

[69 Runner]

True. The 440 will make it quite nose heavy. A Dart with a 440 is a bullet, but won't turn. So like the others have said, go aluminum, or small block, and/or move the motor down and back in the car.

Also if you can buy or build them, use adjustable sway bars. When I ran Porsches back in the day, I had adjustables front and rear. You want the drop links set so the bar is parallel with the ground at rest. This unloads it. Then using a slider you can bias the car. I could adjust one side, both sides, front, rear, whatever was necessary for a track IF a neutral setup wasn't the best. And the stiff end will let go first.

 

[chrisII]

I can tell you that 71-74 B bodies were pretty much all the same.

on what planet? maybe if you look at the outside the 71-2 look the same as the 73-4, but if you put them on a hoist you will see that the only chassis parts that did not change were the steering box ,center link and tie rods. in 73 everything went isolated and cushy. great for hiway drivers, bad for any kind of racing.

T bars on the 73 are longer, but mounts can be redone to make older ones fit. you can make the older rear springs work. while you are at it ditch the iso rear if you have it. as I remember my 74 charger did not have the iso rear stuff.

Ive never done one for auto cross, but ive had lots of them for circle track racing. we are harder on parts than auto cross. we don't turn right but still learn a lot about making our cars turn. depending how crazy you want to get I can tell you all the little tricks ive found on that front end. my current car has MOST of that K frame, welded in the car . I cut off the whole upper A arm mount and installed weld on brackets for tube uppers (off the shelf cheap racing parts that use mopar ball joints). My car has a full cage and front hoop, however you can make arches from tube for both side upper shock mounts, and tie them together side to side. Then you can use racing shocks, even coil overs if you like so you can stiffen the front and make spring adjustments much more easly than changing bars. there is a TON you can do on that front end if you want. removeing the bushings and welding in the K does lower the car down over the engine and trans some and these cars have short clearance under the hood to begin, but if you can run a scoop or have a bulge hod its worth doing it.you could also drop the car that bit over the K frame without all the other mods and it would look stock. all depends how serious you want to get with this car. my car has a 73 front stub but it is a full out racing chassis.

 

[Revhendo]

Excellent info. Thanks Chris. I would enjoy seeing some pics of your work.
Sorry I am a little off on my reply time. I was fishing in the Sierra's. The boss is upset, the kid had a great party and the dog said that was the last time I go without her. But I had a great time.

The Roadrunner isn't going serious race only. I am just going for the fun weekender and to upset a few (ok, alot) of the wanna be's. I already have solid bushing for the K-member. I found that a set of first gen Camaro subframe solid mounts will work for the T-bar mount. I am welding in 2X3 square tubing for subframe connectors. I am considering extra bracing for the front longitudinals, but want to get the 440 in first.

69Runner, good tip on the adjustable bars. I will look into it. Getting a bar in place of the lame stock one could be interesting.

And I know that to be really serious about this deal, I should keep the 340 stroker in it. But, that motor is getting redone and going into the Valiant. Besides, nothing beats the sound of a screaming 440 going through the gears.
(OK, maybe a screaming hemi, but hey, I gotta feed the kid.) (and the dog).

Keep the info coming, it's all appreciated and could help more people than just me....

Rev.

 

[69 Runner]

Once again I've managed to prove "to get the correct answer, just post the wrong one" lol
Someone will decide to jump your *** for it.....

on this, or any other planet

 

[chrisII]

sorry man, was a bit tired n cranky that morning.

I do agree about beefing up everything...everything but the part that you prefer to have fail. if you take a hard curb shot (in my case wall) something HAS to give. if you make lowers too tough you end up replacing or repairing the K member. for this reason I do not over stiffen lowers, making sure i leave them soft enough to give in a hit.

 

[69 Runner]

That'll learn ya to get movin without yer cup O coffee:yes:

 

[chrisII]

lol, what I needed was to get to bed. Im backwards sleepin in the day livin at night. sometime round 2 or 3 pm im needin the coffee

 

[69 Runner]

Been there, done that. Ain't no fun.

My condolences