Sub frame connectors needed?

[craigbred]

I have a 71 Challenger R/T. Front and rear suspension is stock, both sway bars and bushings stock, decent shocks around and new bushings in the front suspension. I have a newly installed 505 stroker with a TF727, tight 9.5" converter, 3.91 soon going to 3.55 gears, 28" tall "M/T street" drag radials. I NEVER plan to run slicks. My buddy has a 10.9 sec. drag car (with slicks) and feels my car runs about that good or slightly better. So without slicks, I might be mid 11s.

With clean tires on nice black-top, when I launch the tires chew pretty good, shutter a bit, and then hook up, before hitting 2nd. The car does seem to lift the front some, so I guess it's transferring some amount of weight to the back. I never drove a 10 or 11 sec. drag car with slicks, so I don't know how much "snap off the line" that has compared to my drag radials spinning a little.

So far I launched 5 or 10 times (on the street) and the car seems fine, door close normal.

So the big question, at this level of performance and running drag radials, have you guys seen a Challenger get twisted without frame connectors? I'm hoping to get away without them because they are such a pain to install.

Thanks.

 

[fasjac]

I would say if you’re going to be running it with those tires and launching it, put some connectors on it. There’s plenty of choices or you can make em yourself and only weld on either end. The type that contour the floor requires a bit more welding. JMO

 

[70chall440]

I know there are people who will say not to but I put SFC on every car I build. They GREATLY stiffen up the car overall and offer a lot of benefits and in my opinion no negative side affects other than not looking stock. I aware there is some BS video with that idiot UT who blathers on about how the car needs some flex to which I say "BS". If it were a daily driver resto stock car then probably not but if you have any level of decent performance and if you want the car to handle, proper bracing is required.

 

[Kozlow]

I installed USCarTool frame connectors on mine, and I really like how the car feels now!
Actually I installed the frame connectors, front and rear torque boxes, inner fender braces, and core support brace.

 

[moparleo]

Even without your list of "Performance " additions, all unibody cars especially 50 year old ones will benefit from any type of "frame" stiffening that you do. Ultimate benefit go with the stage 3 USCT kit. Stiff is better for your cars handling, braking and acceleration.
One of the main reasons for roll cages beside driver safety is it ties the front to the rear of the car and stiffens the whole assembly. Just like frame connectors only better.

 

[challenger6pak]

Looks like your car is together. Interior will have to come out with the USCT connectors. Hotchkiss connectors only have to be welded at the front. It is an option if you don't want to take your car apart.

 

[tonysrt]

You have to remember that unibody was the worst thing to happen to Muscle cars. All the power is distributed to the floor pan from the front subframe bolted to the Kframe . From the floor pan twisting under power it moves that force to the actual body parts like rear quarter panels etc.. I have 71 Cuda and only recently put in a welded 1" X 2" connector welded in. I also have a Gen2 Hemi and 5 speed tremic that adds extra strain to the body.

 

[Chryco Psycho]

Because a frame built on a single plane like GM is better ?? Not really !
Yes I would add connectors !

 

[craigbred]

Thanks guys.
Since I really do not want to take the interior out to weld in the floorboard type, the Hotchkis looks like the type for me. Does anyone make a kit that uses round tube instead of rectangular tube like Hotchkis?

 

[70chall440]

Tubular E-body subframe connectors Mopar Cars Dodge Challenger, Plymouth Cuda, Barracuda

Tubular subframe connectors. Double rail and XRT subframe connectors. E-body Mopar Plymouth Cuda, Barracuda, and Dodge Challenger 1970-74

www.magnumforce.com

 

[tonysrt]

If a full frame isn't better why do they sell a full frame to put under a Cuda? Why are we using sub frame connectors to make a full frame? A full frame is just better.

 

[moparmarks]

Sorry but Chevelles and Vettes make great drag cars because of their full frame and are able to launch harder than a unibody. Period.
Put both an Mopar convertible and a GM convertible on a lift and compare them. Even with fully welded in frame connecters the Mopar will flex and sag so much more then the full frame car. The GM vert will act like a Mopar hardtop. Pretty much no flex.

 

[moparmarks]

I used the Hotchkis bars on a hardtop and they are ok.

 

[70chall440]

If a full frame isn't better why do they sell a full frame to put under a Cuda? Why are we using sub frame connectors to make a full frame? A full frame is just better.

They do, Art Morrison, Schwatrz, the roadster shop, etc. However a full frame is a lot more expensive and harder to install than sub frame connectors.

I have installed a variety of connectors but prefer the USCT versions. Yes they do require the seats and carpet come out but the end result is a super clean install that looks like it was always there (or should have been). Once they are in you can jack the car up on them if need be. All of the other connecters merely connect the front clip to the rear which is fine but offer limited advantage, the USCT connectors actually add to the overall structure of the car.

 

[Mopar Mitch]

Personally, I like the Magnun Force twin tube design (and weld them in)... they are low-slung for ground clearance and appear to be slightly bent to accommodate the contour of the bent E-body floor. I haven't installed SFCs yet because different clubs that I race with have different rules for SFCs. The contoured fully length weld type are not allowed for some clubs/rules; others that would require cutting through the floor board are also not allowed. When I do eventually decide and install, I'll let it be known.

 

[moparmarks]

Magnun Force twin tube design. I did one theirs to on a 71 Cuda vert but I just bolted them in. Don't think they did a whole lot on a vert. Maybe better for a H/T.

 

[moparmarks]

Years ago I finished a 70 Cuda vert that had an Art Morrison full frame in it. Man what a pain in the ass that car was. That frame setup moved so many body components. Firewall, floors, hump etc. You don't want one of those unless your building an extreme road course race car which this car wasn't.
It was by far the stiffest Mopar convertible I've ever seen.

 

[70chall440]

I will say that I would not give Magnum Force one penny of my money. I helped a friend put a MF front K frame and suspension on a client's car and it was a nightmare, horrible system. Looking at their SFCs, I am not too impressed with them.

 

[moparleo]

It just sounds like someone wants something but doesn't want to do the work. If you don't want to remove the interior or whatever, just pay someone else. 10 second cars take work and it is not always the easiest or cheapest way.. Nothing comes for free.
Chevelle's and other GM's make so much better drag cars ?? The top cars in S/S are Mopar . GM is Cheaper to race because the parts are cheaper, not better. Always been that way.

 

[moparmarks]

Don't twist my words Leo. I said great, not better. Not talking cost either. Just stating how well full frame cars launch. Nothing more.