US Cartool, QA1, Hotchkis Combination. Need help.

[Swamp Donkey]

      Hopefully this will all make sense. I have a vision for my car, but not sure if everything will work together.  For starters, I want to get a LEVEL 3 CHASSIS STIFFENING KIT 70-74 E-BODY US CAR TOOL MOPAR PLYMOUTH CUDA BARRACUDA. This will include the mini tub kit that I would probably like to install.

2nd on my list is a Hotchkis TVS.  The QA1 will most likely only be for the K-member.  Unless others on here think the complete QA1 suspension is better or comparable to the Hotchkis.

So, one question I have is the rear suspension.  With the us cartool kit, it has rear leaf spring relocation.  Wondering if the Hotchkis rear anti swaybar will still work with the rear leaf springs moved.

Another question is what else I need to order besides lower control arms and torsion bars because it looks like the Hotchkis TVS does not come with these.

Any support would be greatly appreciated. 


http://store.uscartool.com/Level-3-Chassis-Stiffening-Kit-70-74-E-Body-US-Car-Tool-Mopar-Plymouth-Cuda-Barracuda_p_155.html

https://www.hotchkis.net/product/tvs-total-vehicle-suspension-system-1970-1974-plymouth-cuda/?mk=&yr=&md=&sm=

https://www.qa1.net/suspension/handling-suspension-kits/mopar-handling-kits/71-72-mopar-bbody-70-74-ebody-handling-suspension-kits

[72bluNblu]

What is the planned use for the car?

Personally, I don't see the point of a full 3" spring relocation and mini-tub on an E-body. You can fit 275's without cutting or moving anything. If that's not enough, a DoctorDiff 1" offset kit will allow you to run 305's at least, more likely 315's. That's with stock wheel tubs and just moving the spring perches, which is a piece of cake compared to a full 3" relocation and mini-tub. So what I'm getting at is what size tires do you really need to run? And is it worth the time and effort needed for the mini-tub?

As far as the Hotchkis TVS goes, there are a couple things I'll mention. First, it includes sub frame connecters, which are also part of the US Cartool kit. I've installed the Hotchkis connecters on my Challenger, and a set of US Cartool connecters on my Duster. The US Cartool connecters require more fitting, and a TON more welding. They take 3 or 4 times as much time/labor to install compared to the Hotchkis connecters. The style is a little different, but honestly I don't think there's a huge difference in strength either way. And unless you're planning a full finite element analysis you won't know either.

I run the Hotchkis UCA's on my Challenger. The first set of heim joints only lasted 7k miles before two of them wore out. That was before they offered boots for them, and Hotchkis provided me with replacements and a set of boots. But after another 7k miles, I'll say they won't see 10k before they're in need of replacement. Now, those were year round, daily driver miles. But given that the front mount relocation makes the alignment harder to dial in, it's not something I'm a fan of. I've avoided heims on UCA's on my other cars. The improvement in suspension geometry from the Hotchkis UCA's is nice, but unless you're building up a serious corner carver I don't think it's worth the downside of the heims.

I feel like for what they are, the Hotchkis steering links are really expensive, and don't make a huge difference compared to regular tie rod ends with a solid adjuster (like the ones from PST or QA1).

If your K member is damaged, missing, or you need different engine mounts then the QA1 K is worthwhile. But just FYI, the QA1 K isn't that much lighter if you're looking for weight reduction. Like less than 10 lbs lighter than a stock K. So if you have a good K member, and you can weld, then you can reinforce the stock K with a Firm Feel kit (or make the gussets yourself).

The TVS doesn't include torsion bars, there's a few different suppliers but if handling is your goal don't bother with anything less than a 1" diameter bar. You'll also need good shocks with larger bars, the Bilstein RCD's are good, so are the Hotchkis Fox's.

The LCA deal is similar to the K member, if you have stock LCA's you can gusset them. QA1 makes tubular LCA's. They're nice and they save a couple pounds. They used to allow for some extra suspension travel (about 1"), but the new ones have built in bump stops that mimic the stock travel. I have a set on my Duster, they're a nice piece but again not really a big upgrade in function. 

[Swamp Donkey]

    Thanks for taking the time for such a well written response.  After your reply, I'm definitely reconsidering the mini tub and leaf spring relocating.  The end goal for my car is to have a car that handles and brakes well (safety) and is going to be a pleasure to drive.  I am already in the process of rebuilding a 6.4L hemi to have anywhere around the hellcrate to the Hellephant levels of power.  But a 305 or 315 with today's modern tire compounds should be adequate.  Now I've been researching the QA1 stuff just because it seems like the K member with 3rd gen motor mounts just seems like a great idea.  I have used heim joints on my trucks and they never seem to last so maybe I will steer clear of the Hotchkis stuff except for the rear anti swaybars and leaf springs.

I see while looking at the QA1 stuff you can order their kits with or without shocks if you think there are better shocks.

[303 Mopar]

I have tubular steel subframe connectors that made a big difference in the solid feel on the car.  I also would highly suggest the Hotchkis torsion bars (1.10), front and rear sway bars.  I also added their fox shocks with the front being adjustable.  I think the tubular k member and UCA's are over kill.  You may consider a radiator support and inner fender reinforcement, but I do not have either.  I'm currently running 245/45/18 and 275/40/18's with no mods or rolling of the lips and found handling to be excellent.  Regarding brakes, I have not had good luck with Wilwood so would suggest another brand or going with Cass's kit at doctordiff.com. You will want hydraulic brakes or dual booster because the Gen III's do not have enough vacuum for a single booster.

[72bluNblu]

    Thanks for taking the time for such a well written response.  After your reply, I'm definitely reconsidering the mini tub and leaf spring relocating.  The end goal for my car is to have a car that handles and brakes well (safety) and is going to be a pleasure to drive.  I am already in the process of rebuilding a 6.4L hemi to have anywhere around the hellcrate to the Hellephant levels of power.  But a 305 or 315 with today's modern tire compounds should be adequate.  Now I've been researching the QA1 stuff just because it seems like the K member with 3rd gen motor mounts just seems like a great idea.  I have used heim joints on my trucks and they never seem to last so maybe I will steer clear of the Hotchkis stuff except for the rear anti swaybars and leaf springs.

I see while looking at the QA1 stuff you can order their kits with or without shocks if you think there are better shocks.

Don't get me wrong, I love Hotchkis stuff. For the most part they make the some of the best stuff out there. I just haven't gotten very good longevity out of the heims at the UCA's. Which I found a little surprising, I have QA1 adjustable strut rods that use heims on my Challenger as well, and those have seen 70k miles with no issues. So for me the only Hotchkis parts I avoid is the UCA's. The steering links would likely be fine too, I just don't think they're really a big upgrade in function for the price.

With that kind of power I would definitely do some significant chassis stiffening, the Hotchkis subframe connectors are really nice. I would also look into adding torque boxes and some kind of front end stiffening, either US Cartools inner fender and lower radiator support or something similar. On my Duster I use "J" bars, basically similar to the front half of a roll cage with bars tying the firewall to the shock towers to the ends of the front frame rails using landing plates to the chassis. I also run a tubular lower radiator support brace on that car. On my Challenger I'm going to be using Magnumforce's "forward strut braces", basically the same thing as the "J" bars on my Duster.http://www.magnumforce.com/magnumstore/shop/item.aspx?itemid=21 I also have a tubular lower radiator support brace for the Challenger as well. The US Cartool parts are nice for that though because they're not in the engine compartment, so they're a little more subtle and will still provide a significant improvement in chassis stiffness.

For shocks I've run both the Bilstein RCD's and the Hotchkis Fox's. I actually was able to switch from Bilsteins to Fox's on my Duster, got a chance to buy set of the Fox's second hand but unused. On my Duster I have 1.12" torsion bars, which is a 300 lb/in wheel rate. I will say with those bars the Fox's are a little better than the Bilsteins. Not a night and day difference, but noticeable. I think that has a lot to do with how high the wheel rate is, on my Challenger the wheel rate is 270 lb/in and I think the Bilsteins do quite well on that car.

I have tubular steel subframe connectors that made a big difference in the solid feel on the car.  I also would highly suggest the Hotchkis torsion bars (1.10), front and rear sway bars.  I also added their fox shocks with the front being adjustable.  I think the tubular k member and UCA's are over kill.  You may consider a radiator support and inner fender reinforcement, but I do not have either.  I'm currently running 245/45/18 and 275/40/18's with no mods or rolling of the lips and found handling to be excellent.  Regarding brakes, I have not had good luck with Wilwood so would suggest another brand or going with Cass's kit at doctordiff.com. You will want hydraulic brakes or dual booster because the Gen III's do not have enough vacuum for a single booster.

I'm going to disagree about the tubular UCA's being overkill. The reason isn't because they need to be tubular, but, all of the tubular UCA's have additional caster built in. Even with offset UCA bushings in the stock UCA's you can't get very much positive caster, usually only in the +3 degree range. With modern radial tires, especially as you get wider in the front, adding a little more positive caster really helps the street manners of the car. I run +6.5* of caster on my Duster, and it's a manual steering, 16:1 quick ratio box with 275/35/18's up front. I run SPC UCA's on it though, they're double adjustable and can dial in just about any spec you want. Even with my Challenger I was running +5.5*, and if I could have gotten more I would have would have added it. Plus, the stock UCA's are now closing in on being 50 years old. For a critical suspension part that's a lot of wear and tear.

Totally agree with DoctorDiff for brakes. I run his 13" cobra style kit on my Duster. Amazing brakes, a big improvement even over the later Mopar 11.75" rotors. I ran 11.75's on my Challenger for most of the 70k miles I put on it, they were great with the larger 11x2.5" rear drums I also used. But the 13" kits from DoctorDiff a definitely another step up if you're planning on going with 17 or 18" rims. The 13" rotors won't fit with 15" diameter rims.

I use a manual 15/16" master on both cars, also from DoctorDiff. I like it much better than the stock power disk set up. Better feel, and with that diameter m/c the pedal effort and travel isn't bad at all.

[dodj]

I installed the Dr Diff 1.5" spring relo kit on my car and I have 315's in the rear. Original wheel wells. Had to remove and re-weld the spring perches inward. Then it is a matter of selecting your wheel and getting the correct backspacing to centre the wheel. I dont remember for sure but I think my 10.5" wide wheels have a BS of 6".