The Dodge Challenger Message Board

I have a 72 which has recently undergone a "frame off restoration" with a modified 440 that "should" put out approximately 500HP. Among others I used Chuck Senatore's Book on "Big - Block Mopar Performance" as well as my "Desk Top Dyno 2000" to design the engine. The Tranny is a beefed up 727, TCI 3000 Stall Converter and reverse manual valve body coupled to a 3.23 Sure Grip Rear End (it came with the car so I thought I would give it a try.) For Tires I have BF Goodridge 255/60R 15's.

My question is; before I start "pushing" the car after the initial 500 Mile break in period should I stiffen the frame? I am getting various opinions locally from, "it is not necessary" to "it is an absolute must." A mechanic I know does not think it is necessary with my existing tires, that the tires will "Break Loose" before the frame would twist, however he does recommend I stiffen the frame if I go to a larger or stickier tire.

I have put alot of time and $$$ into this car and I would hate to make a few 1/4 Mile passes to see what the car will do then discover that the doors will not close properly.

I figured I would ask those that should know because they are those that do and thats you guys (and gals.)

I can tell you that you do not need them for drag racing with street tyres.

HOWEVER!
If you ever use slicks you MUST or the car will bend. I have heard of the rear window popping out!

I also found with my car that it did indeed feel like a better car when being pushed around our twisty roads. Some of the rattles disappeared as well.

So although you don't need them with street tyres I do recommend them.

I gather, Dave, that you have frame connectors installed on your car? Then ou would know how much is would cost to purchase a set of connectors and the difficulty level of the installation of these frame connectors. WIll they also add alot of weight?

They don't add a lot of weight Joel but they do stiffen up the car and make it feel better. I had mine professionaly fitted because I was having the chassis checked out for straighness at the same time and it was only an extra couple of hundred of your bucks to get the connectors welded in as well.

I would make my own normally. Just use two lengths of 2x2 steel about 42 or 43 inches long. One end of each welds to the trans/torsion bar crossmember and the other you can shape slightly and weld to the box section in front of the leaf spring mounts.

Do not use the bolt-in type.

What made you decide to buy the frame connectors instead of making your own? Where did you purchase your frame connectors from?

Sorry I must not have been very clear.

A workshop that builds race cars and Chassis etc was checking out my car because I thought there was a good chance it was not quite straight.

I did not want to weld in connectors until this was checked. It turned out they thought the car was straight so I asked them to weld in some frame connectors for me while it was there. They had one or two other little jobs to sort out so I thought 'why not'?

Much easier for them to do it. Being a chassis builder they just made the connectors themselves.
I would have to find the steel and spend ages welding on my back setting myself on fire with the sparks. These guys can just lift to car in the air and work in comfort.

Like I said they are only two lengths of 2x2 steel about 43" long. I had a look at my car to see exactly were they welded to.

The front welds to the back of the trans/torsion bar crossmember. The bottom edge of the connector is flush with the bottom edge of the crossmember. The 2x2 bar is positioned just under the hole that something runs through. I can't remember what that was now. Is it the fuel line on one side and the brake cable on the other? Anyway. There is a hole in the crossmember on each side and it welds just under that.

There is a gap between the 2x2 and the floorpan so that the brake cable passes over it.

The rear bit welds on top of the rear chassis next to the box section the rear springs bolt to.

A straight bar will not sit flush on here so the end of the 2x2 has been cut off and welded back on at a slight angle so that it sits flush. They also made the end look neat by cutting a diagnal off it so it tapers down at the end.

That makes it so much clearer, thanks, Dave. Can I ask you one more question that deals with suspension? I notice that a lot of people use traction and ladder bars to kept the rear leaf springs from winding up at initial acceleration, keeping the wheels from hopping and losing traction. I know Mopars use something called a pinion snubber, which comes standard on the car from the factory, I think. From what I understand about what this snubber, I think that it bolts directly to the rear axle, does is when the rear axle begins to wind up, a rubber tip on the bumper will come into contact with the floor pan. Mopar Performance parts sells a beefed up pinion snubber for performanced based cars, adjusting the height to the floor pan, depending on individual requirement. Would this take the place of a traction or ladder bar? Which rear end came with a '72 Challenger with a 318, 8 1/4' axle?

I wish you would start a new thread when you change the subject Joel!

Mopar rear leaf springs are the best in the world in my opinion. What makes them the best is the fact that the axle is not located in the center of the spring. The front half of the spring is shorter and thicker than the back half. The front half gives stability and control to the axle and the back half gives a nicer ride. Just in themselves they suffer very little from axle wind-up or hop.
The pinion snubber controls the little axle wind-up that is left. When racing you want only a quarter inch between the floor pan and the rubber snubber. On the street you need more or it will be hitting the floor every time you go over a bump.
JS Challengers have a re-enforced section on the floor here.
There is no need to fit traction bars to a Mopar.

I don't understand your last line.

Mopar Performance only sells adjustable snubbers for 8 3/4' and 9 3/4' axles.

Oh you are asking which axle you have on your 318??

It could be a 7.25" or more likely a 8.75".
Rallye Challengers all got the 8.75".

My brother says the 8 1/4" had welded gear housing covers and not the bolt on ones? Does that seem correct to you?

I dunno. Listen to what I am telling you. Challengers did not come with an 8 1/4" axle.

Actually I made a mistake. You could have a 7 1/4" in 70-71 with your 318 but from 72-on they all got the 8 3/4" axle. These do not have a bolt-on cover on the rear. The whole carrier unbolts and lifts out from the front.

Oh, kay thats a new one. I will be sure to pass this new enlightening information to my older brother. He will be surprised to know that all this time he had a 8 3/4" rear end and not a 8 1/4". I have to find the build sheet to my car. I am wondering if the 8 3/4" rear end was one of the options that put my car into the higher price class. The casing is too big to be a 7.25".

dave,whould you recommend frame connectors for a car that was not going to run up the strip,also where did you get your chassis checked out,was it hauser racing
many thanks bryan

If I was worried about originality I would not do it but it has made my car feel more solid when chucking it around. The stiff suspension might have been putting more flex into the body than a stock set-up would.

I think I would do it again if I bought another one even if it was just for the street. Unless it was a correctly restored car.

Yes Geof Hauser checked to see if it was straight. But he was not sure if he could put it right if it was not.

thanks dave

Can the sub frame conector be used as a jacking point?

I would guess so if it was made from strong enough box steel but why would you want to when you have a good solid chassis front and rear?

Here are the long awaited photos of my frame connectors.

Made from 2"x2" box steel.

Here is a bigger view. The connector is in line with the subframe leg. Note my modified A-body offset spring hanger.

Here is a shot of where it welds to the trans cross member.

All the welding around the angled back end is because the connector will not sit flush against the bottom of the car. It has to be either cut to sit flush with an angle grinder or (as in this case) cut and re-welded back on with a filler piece added to the gap.

dave you mentioned in an earlier thread that you thought that you chassis might not be straight what made you think this,the reason i ask is on my back wheels if you look at them from either side of the car one doesnt sit central in the wheel well i have measured from the wheel to the edge of the arch and there is a quater of an inch differance between one side and the other.i hope you understand what i mean (one wheel to the bottom of the arch measures 3inches and the other wheel measures 3.25 inches to the bottom of the arch)
sorry its so long winded.BRYAN

That is a lot. The difference maybe in the bodywork if there has been a repair in that area. Or it may be that one rear spring has more camber than the other? If not the axle can be adjusted by a shim behind the forward spring mount. But it is far better to take your measurements wheel-to-wheel rather than rely on the bodywork.

I thought my car could be twisted because no matter what I did it was higher on one side at the back than the other. Even when i swapped the springs from side to side. The front was level though.

I got Geof Hauser to check it as he likes this sort of job. Turned out I had more load on one front torsion bar than the other. This does not always make the front sit funny but changes the height of the opposite side at the rear of the car.

Dave, my car sits higher on the passenger side rear than on the driver side. I have the battery relocated to the driver side rear but that has no effect on it. I noticed that my driver side torsion bar is screwed in more which acording to you earlier that would be the cause of the back sitting higher. Should my first action be to unscrew the torsion bar until its level or try something else first. When I took my rear end off I checked my springs and they are exactly the same.

You want the front adjusters screwed in the same number of turns each side if possible.

I didn't make them like this. the alignment shop did. So this is what I should do first?

Sorry if I was not very clear. Yes start by adjusting the two front torsion bar adjusters so that they are screwed in the same number of turns.

Make sure you are on a FLAT surface and measure the front end suspension height FIRST so you can return it and keep your front end alignment settings.

The car should have been made to sit level to start with BEFORE any other alignment adjustents to camber/caster/toe.

The battery should also be installed on the passenger side of the trunk.

Stock R/T suspension made the passenger side rear sit a little higher so that under hard acceleration the car moved level. So don't worry about it too much.

Mine is a quarter inch lower on the passenger rear. Never did get it sorted out exactly. I gave up worrying about it.