Ok, this all makes sense. QA1's replacement parts for the torsion bar set up are good, I use a few of their parts. I wouldn't do their coil-over conversion, but it doesn't sound like that's the way you want to go. Hotchkis also makes great parts, but they're expensive and there are better "bang for you buck" parts out there for most of their parts. And some of their stuff I would not use on the street. I ran their tubular UCA's on my Challenger, and the heim joints at the UCA's only lasted about 7k miles. Hotchkis warrantied them for me, but even the replacement set is showing wear after another ~7k miles. For a street car I prefer to keep everything with bushings, although I replace all the rubber bushings with polyurethane or Delrin because they perform better and will last a lot longer if properly cared for.
The next thing is- I'm not a supplier or in the business of putting together kits. I have put together a few lists of parts with other retailers based on what I use on my own '74 Duster, which I use as my daily driver the majority of the time. The next big question for you is whether or not you want to just bolt everything on. This is my list for new parts everywhere, basically the closest you get for a full bolt on kit unless
@BergmanAutoCraft has some updated offerings. I updated it at the end of December so the prices should be fairly accurate. This is the grand daddy of everything list, I put it together for a price comparison for all the guys that want to convert to RMS coil overs. So, with that said, there are a several large, expensive items that can be removed from the list if you want to save some money or are willing to rebuild some factory parts.
QA1 Adjustable strut bars - $286.95
1974 DODGE DART QA1 52311 QA1 Dynamic Adjustable Strut Bars | Summit Racing
QA1 LCA’s - $560.95
1974 DODGE DART QA1 52307 QA1 Mopar Control Arms | Summit Racing
QA1 tie rod sleeves- $80.95
1974 DODGE DART QA1 52325 QA1 Heavy-Duty Tie Rod Sleeves | Summit Racing
Proforged tie rod ends- $174.08 (all 4)
1974 DODGE DART Proforged Chassis Parts 104-10157 Proforged Tie Rod Ends | Summit Racing
https://www.summitracing.com/parts/pof-104-10156/make/dodge/model/dart/year/197
Proforged lower ball joint (driver)- $45.80
1974 DODGE DART Proforged Chassis Parts 101-10129 Proforged Ball Joints | Summit Racing
Proforged lower ball joint (passenger)- $45.80
1974 DODGE DART Proforged Chassis Parts 101-10128 Proforged Ball Joints | Summit Racing
Hotchkis Adjustable Shocks- $423.50
1974 DODGE DART Hotchkis Sport Suspension 70030013 Hotchkis Sport Suspension Tuned 1.5 Adjustable Performance Series Shocks | Summit Racing
Proforged ball joints- $42.38 (both included)
1974 DODGE DART Proforged Chassis Parts 101-10126 Proforged Ball Joints | Summit Racing
Moog idler - $35.99
1974 DODGE DART Moog Chassis Parts K7086 Moog Replacement Idler Arms | Summit Racing
Hellwig 55905 front sway bar- $297.03
1974 DODGE DART Hellwig 55905 Hellwig Motorsports Tubular Sway Bars | Summit Racing
Bergman Autocraft SPC UCA’s (1st gen)- $495
BAC/SPC 1.0 UPPER CONTROL ARM - Bergman Auto Craft
Bergman Autocraft 1.08” torsion bars- $385
Mopar A Body Torsion Bar Set 1.08" - Bergman Auto Craft
Proforged polyurethane control arm shaft kit w/bushings- $116.95
1974 DODGE DART Proforged Chassis Parts 120-10003 Proforged Control Arm Shaft Kits | Summit Racing
Proforged Camber bolts - $36.04
1974 DODGE DART Proforged Chassis Parts 120-10009 Proforged Camber Bolts | Summit Racing
DoctorDiff 73+ spindles- $175
Mopar Reproduction Disc Brake Knuckles for A/B/E Bodies
Borgeson box from BAC $849
BAC STEERING BOX CONVERSION KIT - LARGE SECTOR 73-82 - Bergman Auto Craft
Front total: $4,092.41 (power steering, pump and lines not included, that's for the RMS comparison part)
The rear suspension isn't a part of most of the kits, but here's a good start
Rear :
Hotchkis Sport Springs- $463.37
1974 DODGE DART Hotchkis Sport Suspension 24385 Hotchkis Sport Suspension Leaf Springs | Summit Racing
Hotchkis 1.5 shocks (adjustable)- $423.50 (both)
1974 DODGE DART Hotchkis Sport Suspension 71030015 Hotchkis Sport Suspension Adjustable Performance Series Shocks | Summit Racing
Hellwig rear sway bar 6907- $440.15
1974 DODGE DART Hellwig 6907 Hellwig Anti-Sway Bars | Summit Racing
Rear total: $1,327.02
Complete total: $5,419.43
Now, that list may be (and probably is) above and beyond what you want for the street. Most folks are happy without adjustable shocks, so you can save a bunch of money there and the Bilstein RCD's are very good. You also can save a TON of money if you rebuild your lower control arms and just box them vs using new tubular LCA's. And you may be able to reuse your stock camber bolts (and should if your are in good shape). Reading your first post you may already have disk brakes too, so you don't need the spindles. I'll leave the bolts and spindles in. If you make these replacements to the above list-
Bilstein RCD shocks front- $270
BILSTEIN SHOCKS - FRONT - A BODY MOPAR - Bergman Auto Craft
Bilstein RCD shocks rear- $254
BILSTEIN SHOCKS - REAR - A BODY MOPAR - Bergman Auto Craft
BAC lower control arm reinforcement plates - $30 ( to be welded to the factory LCA's)
Lower Control Arm Reinforcement Plate/Pr - Bergman Auto Craft
Ditching the Hotchkis adjustable shocks and QA1 tubular LCA's saves you $854.01 and brings you down to $4,565.42 for everything, front and rear. And that may still be a few hundred too high if you already have disk spindles.
Another item is the SPC UCA's. They're super nice, but for most street cars you don't need them and their adjustability will make it difficult to find an alignment shop that wants to deal with you. You can run QA1 UCA's, which come with upper ball joints, and should still have enough adjustability for a reasonable modern alignment with decent positive caster numbers....
QA1 Tubular UCA's - $436.95
QA1 TUBULAR UPPER CONTROL ARMS - Bergman Auto Craft
That saves you another $100.43 vs the SPC's. Personally, I think the SPC's are a much better part, but again, for a street car they're not necessary. I do love mine though, but I also do my own alignments.
Anyway, that gives you a list to pretty much fully rebuild all the suspension on your car. Clearly it uses a bunch of different parts, but I have run pretty much all of the parts above on my own cars for at least 30k+ street miles, and some as far as over 70k miles on my Challenger. Only thing I haven't dealt with at all is the Borgeson power steering.