My Dart has 1.12" T-bars as well as an Addco 1-1/8" front sway, albeit with the crappy stock mounts. It handles great on the track, but it's not comfortable on the street.

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Somehow I ended up owning three 1964 slant six A-bodies. I race one of them.
Escape Velocity Racing

Just some food for throught:
- Do the research to figure up the wheel spring rate with a given bar.
- Then figure the approximate front corner weight for your car; I would expect many A's to be around 800-900 lbs total weight per front corner. Subtract an approximation of the unspung corner weight (typically the wheel, tire, brake and spindle assembly, and half of the shock and control arms weight). This all gives you your sprung corner weight.
- Then use the wheel spring rate and that sprung corner weight and you can see how many inches of loaded suspension travel correspond to that corner weight and wheel rate. With a 1+" bar, that numbers of inches will be significantly less than the full available suspension travel.
- When you get a transient corner situation where the wheel completely unloads due to too stiff a spring, the car's tire traction on that coner abruptly changes.

That is the issue that you need to think about with large, very stiff t-bars on roads that are rough in roadbase with sudden undulations, or a rough, irrregular surface: sudden unloading of the tire on one corner because you just 'ran out of spring'. No problem on a smooth track or autorcross surface. No what you should want on a rougher mountainous roads. In the southern Appalachians where I live, it will be an issue.

BTW, the same car competing in a rally (where full usable suspension travel is at a premium) will typically use a spring rate anywhere from 25% to 50% LOWER than the spring rates for track/auto-x use in the same car.

Good info, thanks!

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Casually looking for a Clifford hyperpak intake for cheap.

Also realize that the anti-sway bar's effects on weight transfer will be either neutral (for a straight 'jump' over a bump) or can unload the inside tire even more in addition to the wieght unloading described above. And, in transient situations, a shock that is well matched to a stiff spring rate for good all around control will simply be 'too stiff' for a very abrupt transients and hinder the tire's tracking sudden surface changes. Shock valving can be made to help this (research rally shocks), but too stiff can only be fixed so much. So it is a multi-variate problem.... (And I sure don't feel I have a complete handle on it, so this is why I say 'food for thought'.)

The most obvious 'problem' situation is rounding a corner hard and suddenly encountering a bump, or encountering a sudden drop in the road surface.

Hmmmm. I might leave the stock t-bars in there until the car is actually driveable and I can get a feel for how it rides and handles. It doesn't have a front or rear sway bar, yet. The only upgrade has been the factory 6 leaf rear springs. As I mentioned above, it does have the 225/AC bars, which are a step up from the stock 225 bars. I have lost some weight off the front end by dumping the 1974 front bumpr with the 5 mph crash shocks and switching to a 1967 Dart front bumper. I will also try and save some weight by converting from the old v-twin AC compresser to a modern aluminum housing Sanden type compressor.

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Casually looking for a Clifford hyperpak intake for cheap.

I personally would not be hesitant to change up into the .9" range at all. It is when going over 1" AND you're driving on rough, uneven roads that I would be getting hesitant due to the factors I mention... for my driving environment. And I would be spending the $$ and changing out to Bilsien shocks in the .9" range, based on direct past experience of what they do.

Now, the ride is another factor altogether.

In our rough part of the world (1930s highways full of curves and holes) I like the Soft T Bar.....Big Sway Bar....Best Shocks you can afford combo.

A sway bar added to stock T Bars stiffens everything up and better distributes load to both sides.

I found the bar I want is the one that gives me the ride height I want and provides enough action to let the snubber just bottom out on the worst compression I can imagine. Rebound control is then maximised.

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Yeah....Im the one who destroyed this rare, vintage automobile.....

I stumbled on this comment, and since there were no further replies, felt it warrants comment. "stiffens everything up" is rather subjective, and not sure it truly relates to a swaybar, but "better distributes load to both sides" is actually incorrect, and the weight is really distributed with more bias, to the outside. This better distribution idea, is a very common incorrect understanding of a swaybar in use. It does however keep the chassis from leaning, among other things. The reason for that reduction in lean, is mostly misunderstood. I could explain all day long, but the light bulb will not go off, until a person thinks thru for themselves, the motion and forces at play. Start with, as outside tire/spring is compressed in a turn, that side lifts the swaybar end on that side, which transfers that motion, according to to the diameter/stiffness of the swaybar, to the other inside tire/spring, when those forces arrive, they proceed to try to lift that inside tire off the ground, which means that side's spring is no longer pushing down, with as much force, and viola, less lean. The front swaybar also induces greater understeer, if no other changes are made. Does this help?

Thinking of forces exerted on various components reminds me of indeterminate structures class during my CE studies many moons ago where an IBM 360 and home made programs conjured up in conjunction with Frotran class were used to estimate all the moments... Looking back congers up a thousand ZZZZZZZZ.

All I'm going to say is that in 2008 when rebuilding my 67 Dart ragtop's beyond worn out suspension, one inch+ bars were the talk of the town that I took with a grain of salt. (sorry about the cereal clichés there) Anyway, where a convertible is plagued with terminal chasses flex, when retro fitting a (at the time) 45 year old heap's suspension I decided that 0.941" bars would be a decent match to the six leaf springs Reed lists above, Monroematic gas shocks, and Addco 1 1/4" front anti-sway bar with reengineered mounts somewhat like the factory used, and all new bushings; plan was to mimick the Cuda S handling package used in late sixties. (also I added sub frame connectors, and being a rag top, all four corners came with factory torque boxes, two items I would recommend to stiffen up a fifty year old car to aid suspension dynamics.)

Maine still has a lot of high crowned back roads left over from WWII days perfect for traffic free top down cruising, and a majority being two lane modern flat wide paved shoulder two lane major state & federal routes.

Previously this car felt as it was two different cars attached just behind the front seats of different manufacture with a big sloppy hinge; it was a flopping mess. First drive post rebuild was stunning in the way the old girl stuck to the road nice and flat in corners, not harsh (no bottoming out on rubber stops) on uneven crappy pavement, and no nose dive under hard braking feeling as one machine; I now have rolled on about 25K miles with this combo and still like it.

The Dart rides a bit softer than my 300C AWD which is sprung a bit stiffer than a two wheel drive LX chasses (300, Charger), Dart's front and rear feel balanced in suspension movement, no rear sway bar, and no over steer.

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67' Dart GT Convertible; the old Chrysler Corp.
82' LeBaron Convertible; the new Chrysler Corp
07' 300 C AWD; Now by Fiat, the old new Chrysler LLC