I ran my original slant 6 bars with iron head bb in my dart. I re did the front end again and just put a heavier slant six bar in, but now have aluminum head bb.

I would say it of course depends on if its a race or street car. Myself I still run the original bars in my 63. Its an original 383 car and to me they work fine on the street and work fine at the track. I don't think I would want to run the 6 cyl bars on a car that's basically a street car most of the time. Ron

383 is only what, 20 lbs less than a high block.

My BB added 80# to the car over the SB it replaced. Mostly street car, but i want suspension to work best possible at the track. So the 68/69 383 tb is the best option for this?

If you can find a set that's nice,? 340 should be ok, depends on how many miles where on them. My bars for the 69 440 are #895-894 (off build sheet) Can't remember the diameter right now. The SB bars are a dime a dozen, should be easy to find. If street-strip they would be best all around in my book. Aftermarket ones that size would be ok, nothing heavier, it would ride like a tank.

A torsion bar is a spring. Just as with coils, different spring rates (diameters) can be used to adjust how the suspension and how the car reacts in your particular situation. And springs wear out too. More so for a light spring required to store more energy.

I think the 340 bar would be an .870". I readjusted bars both sides again 1 more turn each. Will see if this holds for now.

Also on my sons 72 Dart it was a 318 AC car. We removed the AC and now have a 400 in it but the 400 has aluminum heads and intake and headers. I felt with the AC gone and the aluminum parts on the 400 it may be no heavier then when it had the 318 with AC. So it still has the 318 AC bars in it which have been in it with a bigblock (400) since 1997 with no problems. And it is a street car. Ron

Just sooke with matt at firm feel. He suggests .880 bars for best of both worlds. $325/pr, but out of stock right now. Who else should i call for opinions?

Well that sucks. How long before they get some in?

I think PST has torsion bars. I can't vouch for the quality though. Maybe someone else can.

He did say they might have them tomorrow. Hes gonna call me when they are available. He also said he sells alot of 1" bars for street cars that are not stiff at all. They also have a .820 but said it wouldnt last long.

That bar from mancini might be fine, but i nolonger call mancini for advise on anything.

you can use that part number to search availability elsewhere. i found some .960 bars for my coronet using that method. only paid about ~$250 shipped if i recall correctly.

got them here, if you're in a hurry though, i'd just order from Jeg's...

https://www.moparonlineperformance.com/product-p/p5249150.htm

Always looking for a deal. Thanks

Just received a call back from matt@firm feel. They had to order the material for the .880 bars. Wont be available for another month.

$300 for bars! Glad I have about 10 sets.

Yep. I want brand new. Not used up bars that need to be changed again in another 2 or 3yrs. Magnumforce has .870 bars for $325 as well. Need to give them and hotchkiss a call yet. They are pricey new.

I forgot about Magnumforce.

Made some more calls today. Magnumforce recommended a 1.030 and a 1.080 bar. Hotchkis have a 1.1 bar. Not where i want to go. So i called calvert racing because i use caltrac bars and they recommend 340sb bars as a member here also recommended.