I am doing a full frame-off restoration of a 1971 Cuda 383 convertible. This is an authentic car and I do not want to diminish its value. A few questions:

Should I put in frame connectors?
If so, who makes the best ones?
Will these appreciably improve the stiffness of this car?

Absolutely Install them.Weld in units are the best.But Bolt in ones are better than nothing.I have a 68 barracuda vert, 318 auto car. freshly restored.Frame connectors make the car feel more solid,less vibration,The big plus is no worry about the body panels moving/flexing.Gaps should stay the same as assembled.The best bolt in ones That I see would be the ones from unlawful racing.More expensive than weld-in ones.But nice alternative if you don't want to alter an original car.I did the bolt in ones for that reason.My car has all original metal,I wanted the option to remove them.After driving the car after install,I should have welded them in.I'm not removing them.Car feels that much better with them. http://www.unlawfulracing.com/5.html

USCartool.

If you are doing a correct restoration of a 383 car, you will not need frame connectors . Installing them will hurt the value of the car .
However, if you are doing a "resto mod" do whatever you want that makes you happy.

Greg

After reading your post i understand your dilemma. My friends faced the same problem with thier rag tops. One welded his frame connectors in-the other bolted them in. Both cars have since been sold. The Challenger was not an original car-and it did not matter to the new buyer-that the connectors were welded in. The road runner was an original car-and it did matter to the new buyer that the connectors wre only bolted in. Of the 5 potential road runner buyers/viewers-every one stated they would not have even considered the car-if the frame connectors were welded in. In your scenario i believe you would be happiest with bolt in pieces.

All I can say is don't build your car for the next guy.
Also, anything is reversible.
Even a bolt-in means drilling holes, so will that be an issue to the next owner in itself?
You can take out welded in frame connectors if it is an issue. In fact you could probably argue it would be easier to cut them out athan weld in the holes left by the bolt ins?

Weld in are acknowledged to be much better than the bolt in - so if you are going to do it at all I'd use the weld in.

Does your car have any rust damage that you'll be repairing? Are you going to weld in those patch panels and such? Weld in sub-frame connectors enhance the structure of the car so dramatically, it's almost foolish not to put them in. They help reduce metal fatigue and potential chassis damage on the rest of the car.

I understand the purist's arguements, but weld in connectors can be removed if ever need be. All it takes is a little grinding and touch-up bodywork. You know, the kind of touch-up bodywork that you have to do when installing metal for rust repair.

In my book, unless it's a pristine survivor, by restoring it back to "stock", most people have modified it from original. Most guys over restore or restore incorrectly(myself included), so unless you do your restoration work like Dave from ECS or a big handful of other guys capable of true and acurate restorations. It's all gotta be redone to make it closer to a perfectly-stock, museum piece that doesn't or can't get driven anyway.

What's a little extra cutting, grinding and touch-up to remove welded in sub-frame connectors going to matter in the big picture.

There are quite a few upgrades that these old Mopars can benefit from that are easily swapped back to "stock". The performance and safety benefits for a car that will be used on the roads far outwieghs the work needed to return it to stock in preparation to be a museum piece or trailer queen.

This is the philosophy I use when I am "restoring" my cars. Perhaps, one day when I am too old and am rich enough to afford the true professional restorers, and I don't or can't drive my car anymore, I will have it professionally restored into a museum piece or total trailer queen that just sits locked in my garage between National Mopar Gold OE events. Until then, build it as accurately and true to original as you can, but choose modifications wisely that make it perform better in all kinds of ways, acceleration, stopping, comfort, control and looks without going too far beyond the bolt-on and in this case the small weld on modifications that really enhance the cars performance and safety without forever irrevocably altering it.

If your going to drive the car I would weld them in, us cartool is what I would buy, if the car is just going to sit in the garage as a show piece then dont bother. my opinion is if your not going to weld them in don't waste your time.

I had a customers 71 Challenger 440 Convertible on jack stands and it flexed terribly!There was at least an inch gap in the doors.It was a factory 318 with a 440.

US cartool are nice pieces but if you're worried about resale value you don't want those welded to the legnth of the floorpan...That would'nt be a simple,reversable procedure...

I am putting them in my 1971 ragtop.

I would never even think about buying a street car with subframe connectors, there really is no need! How do you know that the clown that put them in did it right? Every Mopar convertible has reinforcement channels in the rocker panels and I have never had issues with flexing because of them. Of course I have never owned a cheap E-Body, so maybe they are different...

Id get bolt on ones. welding in a couple holes is not an issue and takes a few minutes, but cutting out welded frame connectors can be easily a weekend job. As for the 'dont build the car for the next person' I agree, but you can't say you NEVER going to sell it. Ive passed on some very nice cars because the owner used the Im never going to sell it theary and painted it the wrong color or yes, welded frame connectors, and it was too bad, because they sold for WAY under the market at the time. IMO, I try to make everything that I change on a car easily reversible

Weld them in, either XV's or US CarTool units, the verts flex so much, you'll be sorry later when the door gaps, fender gaps change, or chaffe or bodywork starts cracking, including leaded seams,......really how "valuable" is a 71 Cuda vert to not enhance the rigidity of the body because your worried about "value".....the "value" will/would be less down the road should you decide to sell because the car looks like an unsound "flopper" structually

I most have the only E body vert that isn't a wet noodle.. I can jack up the left front @ the frame rail & the left rear will lift at virtually the same time... I can open both doors while jacked up & they close fine... I raise it on my hoist frequently & again I can open & close the doors no problem.... It's been restored for 15 years & I've driven it 60k+ the doors still line up, the hood & deck lid line up, no cracks, no door edge chips...

FWIW If I had it to do over I might consider the US Cartool SFC's but my car really doesn't need them....

On a nut and bolt "restoration" that will likely see limited road time I don't think I would. If it is going to be driven, and/or you plan on other mods or non-factory changes exterior color, options etc then I would say yes. It is a definite improvement. I have an e-body hard top and a dart convertible both with sub-frame connectors. The convertible was a dramatic improvement in the rigidity of the car after the connectors were added. The hardtop was not as noticeable but it was an improvement.