Charger build discussion

[Brutalowner]

Im finally getting ready to update my Charger to make it perform like a modern LX chassis car, with the primary focus on the handling. The plan seems pretty simple and straightforward, but id like to hear input on the parts selection, mainly bar diameters.
Here is what Im working with-
1969 XP 318/904/ power drums, a/c p/s console car.
Completely stock. Owned since 1982.

What I have for the project.
Blueprint 408 that dyno'd 477hp
a built 727 with appropriate stall
aluminum 1350 driveshaft
8.75 rear with sure grip and 3.23/3.55/4.10- 3.23 being the primary use gear
Mopar XHD springs
15 x 8 Magnums
10.7 rear discs
Disco-tech style 11.7" front discs
tuned up and gusseted LCAs
Qa1 strut bars
Firm Feel UCAs
Borgeson box
1-3/8" anti sway bar
.940" R/T torsion bars
all other front components are new OE style.
275-60/15 Toyo 555S rear, 275-50/15 Toyo 555 in front.

Pretty basic, keeping the traditional 15" look.
Will it need bigger torsion bars than the .940"s? I imagine the weight savings from the Borgeson, the 408's aluminum top end, Sanyo compressor vs. the iron V-2 is considerable, but not having the typical B or RB weight in the nose
should be a help.
The shock selection is also up in the air. I have used the Vikings, and Ride Tech, but not Bilstein. Vikings are nice, but the price isnt. Whats the verdict there?
A rear sway bar- wait and see how it feels, or just count on needing it?
Round two for the car will be subframe connectors, most likely the US Car Tool scalloped style with all the adders, minus the rear frame over-axle plates. I dont plan on any type of cage, so the under car connectors will have to do.
I'd love to take it to a track day once in a while, but mostly it will be driven on twisty Country roads, with a few long straights...
Has anybody strayed from the traditional Big Block build and gone High Rev Small Block? This will be my first one, so any experienced thoughts are welcome.
Thanks

 

[Don Frelier]

275-60/15 Toyo 555S rear, 275-50/15 Toyo 555 in front.

Likely a typo here...

I like the 1.03" torsion bars. Even with a smallblock they would still be an improvement.
Definitely a rear sway bar if you like turns.

 

[Belvedere408]

I really like my Bilstein shocks and 1.03 PST bars.

 

[RJ Squirrel]

 

[Brutalowner]

Likely a typo here...

I like the 1.03" torsion bars. Even with a smallblock they would still be an improvement.
Definitely a rear sway bar if you like turns.

Nittos, my bad.
I have used the 1.03" bars in the past, on a b body cop car. It was not a big leap in stiffness for the BB car, So it might be just right for a LA car.
Thanks Don!

 

[Brutalowner]

I really like my Bilstein shocks and 1.03 PST bars.

Sounds like the 1.03 bars are going to be the choice.
Thanks Belvedere408

 

[Brutalowner]

Here is the Charger. Triple Green/318

 

[ckessel]

Your project sounds great. My 67 Coronet wagon will be getting many upgrades soon, like what you're doing, but not as extensive as what I've done so far on my 65 Coronet[ back burnered while I'm generating project money].

 

[Belvedere408]

Sounds like the 1.03 bars are going to be the choice.
Thanks Belvedere408

I also added us car tool subframe connectors and torque boxes. My car is 67 Belvedere with blue print iron headed 408 and 4spd. Has a front sway bar also.

 

[ckessel]

When you go to weld the structural improvements in, make sure the car is well supported. Either on a 4 post lift or the tires/wheels on cribbing. If its on a two post, [unless its a bare carcass no engine, trans, suspension, interior etc], or on jack stands, the body will sag and you'll have fun getting the doors open or closed after you've welded.

 

[snakeoil24]

Skip aluminum drive shaft

 

[Kern Dog]

The .94 torsion bars are weak. These cars were notorious for having soft front spring rates and stiff rear spring rates. 1.0 should be the starting point for torsion bar sizes even with an LA series engine. I run 1.15" bars in my red car.
Years ago, an outfit known as XV Motorsports put several Mopars on a 4 post chassis jig to put these cars to chassis stress tests. They found thatfor improved handling, the rear spring rates could often stay stock but the front needed additional stiffness. They sold sway bars, torsion bars, leaf springs and other stuff. This outfit was a big proponent in chassis stiffening too. Frame connectors, torque boxes, reinforced core supports below the radiator, etc. US Cartool picked up where XV left off and they sell similar stuff since XV folded up shop.
Rear sway bar? Yeah...It needs to be smaller than the front but the exact size may be hard to determine. It would be fair to start with a rear bar of approximately 70-75% of the size of the front. The 1 3/8" front bar you mentioned is probably hollow and that means it's stiffness is on par with a solid bar close to 1 1/4" size. This means a rear bar around 3/4 to 7/8" may be right but it really depends on the configuration of the bar. Longer lever arms on a bar reduce the effective rate of it due to the leverage increase. A 3/4" bar with 12" lever arms will be stiffer than a 7/8" bar with 16" lever arms.
Some might suggest Hotchkis but be ready to spend a lot. They build quality stuff but you sure do pay for it.
I'm the guy that always looks for a cheaper way before cracking open the wallet.
Front end alignment will really make the car respond well when the road gets twisty. You need more caster than the stock control arms can usually give unless all the planets are in alignment.
I was able to get 6 degrees of positive caster with stock upper control arms because of offset UCA bushings and a low ride height. The geometry of these front ends is such that the lower your ride height, the more caster and negative camber you can have. A car at a stock ride height cannot get as much caster as a lowered car.
Here is mine...

QA 1 makes some good stuff. I have their tubular front sway bar and upper control arms. I was able to align mine to 8 degrees of caster and 1 degree of negative camber. NO, this does not result in increased tire wear, just better steering response and control. A new Challenger R/T has a lot of caster too....

 

[RJ Squirrel]

My 68 I just took apart was a factory 318/904 car with the skinny torsion bars. I was relieved to find out that the 318 in it was not the original so out in the scrap pile it went and a 383/727 is going back in. I will be needing to upgrade torsion bars. As for the UCA's, I modified the stock ones in my RR to move the ball joint aft about an inch, which gave me 5 1/2" caster with the *** end high rake I have. I did that mod after test driving a bit, and it was night(mare) and day improvement. I did have offset bushings on them but they did not help much. I highly recommend aftermarket UCA's or modifying them.

 

[Brutalowner]

The .94 torsion bars are weak. These cars were notorious for having soft front spring rates and stiff rear spring rates. 1.0 should be the starting point for torsion bar sizes even with an LA series engine. I run 1.15" bars in my red car.
Years ago, an outfit known as XV Motorsports put several Mopars on a 4 post chassis jig to put these cars to chassis stress tests. They found thatfor improved handling, the rear spring rates could often stay stock but the front needed additional stiffness. They sold sway bars, torsion bars, leaf springs and other stuff. This outfit was a big proponent in chassis stiffening too. Frame connectors, torque boxes, reinforced core supports below the radiator, etc. US Cartool picked up where XV left off and they sell similar stuff since XV folded up shop.
Rear sway bar? Yeah...It needs to be smaller than the front but the exact size may be hard to determine. It would be fair to start with a rear bar of approximately 70-75% of the size of the front. The 1 3/8" front bar you mentioned is probably hollow and that means it's stiffness is on par with a solid bar close to 1 1/4" size. This means a rear bar around 3/4 to 7/8" may be right but it really depends on the configuration of the bar. Longer lever arms on a bar reduce the effective rate of it due to the leverage increase. A 3/4" bar with 12" lever arms will be stiffer than a 7/8" bar with 16" lever arms.
Some might suggest Hotchkis but be ready to spend a lot. They build quality stuff but you sure do pay for it.
I'm the guy that always looks for a cheaper way before cracking open the wallet.
Front end alignment will really make the car respond well when the road gets twisty. You need more caster than the stock control arms can usually give unless all the planets are in alignment.
I was able to get 6 degrees of positive caster with stock upper control arms because of offset UCA bushings and a low ride height. The geometry of these front ends is such that the lower your ride height, the more caster and negative camber you can have. A car at a stock ride height cannot get as much caster as a lowered car.
Here is mine...

View attachment 1856980

QA 1 makes some good stuff. I have their tubular front sway bar and upper control arms. I was able to align mine to 8 degrees of caster and 1 degree of negative camber. NO, this does not result in increased tire wear, just better steering response and control. A new Challenger R/T has a lot of caster too....

View attachment 1856981

Great info, thanks Kern Dog. I have a set of 1.12" bars on the shelf, I may slip them in on the initial assembly. The 1-3/8"front bar I have already installed is solid, but I also have a hollow Hotchkis 1-3/8 that goes with the 1.12 bars for another project. So with the solid bar, I should be safe with either one of the rear bar diameters? I put a mid 70's Cop Fury rear bar on my 68 R/T back in the 80's and if felt like it wanted to unload the rear, or skate easier. I didn't care for it much, hence the questioning of use. I've installed quite a few for customers at their request. Never any complaints. Makes me wonder if they don't drive hard enough, or was there something dumb with my fabbed install 30 years ago. Maybe it was the NAPA farm-truck edition HD shocks from Regal Ride...
What end links are you running in this pic? I like the ball/socket instead of bushings. Is that a 70 K Member thing, since the sway bar is higher, or can they be used with a 68-69 K Member?
My ride height will be on the low side, so I'm hoping to have extra caster. I have offset bushings ready for the FF UCAs, as I don't remember being able to get more than about 4* out of them.
The alignment specs I've always used seem to be pretty basic, for street use anyway -.50 camber +.10 toe (combined) and as much caster as adjustment allows without straying too far from the desired camber.
Thanks to Everyone for all the input here.

 

[ckessel]

The 70 unit is a bit unique as the sway bar goes through the center. A one year deal as the 71/2 unit is the same as an E body which has a different angle on the steering box mount and has a different center link. Sway bar goes through the center of the K. 68/9 units have the same box mount angle as the 70 but as you know, the sway bar hangs out front. Also in there is the mount tabs on the control arms being different for -69 and 70- due to the sway bar. The 63-70 K's can interchange somewhat but there are differences. On 63-5, the engine is forward about 1.5" compared to 66-. The idler arm mount on -67 is a single tab with a bolt referred sometimes as a Bayonet Bolt. 68- the idler is mounted in a double shear plus is more readily available and a stronger mount compared to -67. Going with the heavier spring/bar rates, you would be wise to do the structural improvements to the unibody. Various ways to attack the SFC's with ease of install to complicated. The torque boxes, front apron braces, lower radiator support are good choices. I have seen where USCT even has reinforcement pieces to put into the rocker panel. Might be a good one to do if you need to do replacement on the rockers due to rust.

 

[Kern Dog]

Great info, thanks Kern Dog. I have a set of 1.12" bars on the shelf, I may slip them in on the initial assembly. The 1-3/8"front bar I have already installed is solid, but I also have a hollow Hotchkis 1-3/8 that goes with the 1.12 bars for another project. So with the solid bar, I should be safe with either one of the rear bar diameters? I put a mid 70's Cop Fury rear bar on my 68 R/T back in the 80's and if felt like it wanted to unload the rear, or skate easier. I didn't care for it much, hence the questioning of use. I've installed quite a few for customers at their request. Never any complaints. Makes me wonder if they don't drive hard enough, or was there something dumb with my fabbed install 30 years ago. Maybe it was the NAPA farm-truck edition HD shocks from Regal Ride...
What end links are you running in this pic? I like the ball/socket instead of bushings. Is that a 70 K Member thing, since the sway bar is higher, or can they be used with a 68-69 K Member?
My ride height will be on the low side, so I'm hoping to have extra caster. I have offset bushings ready for the FF UCAs, as I don't remember being able to get more than about 4* out of them.
The alignment specs I've always used seem to be pretty basic, for street use anyway -.50 camber +.10 toe (combined) and as much caster as adjustment allows without straying too far from the desired camber.
Thanks to Everyone for all the input here.

The thing about rear roll stiffness is that oversteer is much more sensitive at increased speed. A car that feels a bit twitchy in a curve at 30 will feel much more so at 60. It is because of that that you want to tread lightly with rear roll stiffness.
The sway bar links are Moog. I've used the straight links in the Charger with LCAs that have the sway bar brackets on them.

I had to cut and shorten them to work.

 

[Brutalowner]

The 70 unit is a bit unique as the sway bar goes through the center. A one year deal as the 71/2 unit is the same as an E body which has a different angle on the steering box mount and has a different center link. Sway bar goes through the center of the K. 68/9 units have the same box mount angle as the 70 but as you know, the sway bar hangs out front. Also in there is the mount tabs on the control arms being different for -69 and 70- due to the sway bar. The 63-70 K's can interchange somewhat but there are differences. On 63-5, the engine is forward about 1.5" compared to 66-. The idler arm mount on -67 is a single tab with a bolt referred sometimes as a Bayonet Bolt. 68- the idler is mounted in a double shear plus is more readily available and a stronger mount compared to -67. Going with the heavier spring/bar rates, you would be wise to do the structural improvements to the unibody. Various ways to attack the SFC's with ease of install to complicated. The torque boxes, front apron braces, lower radiator support are good choices. I have seen where USCT even has reinforcement pieces to put into the rocker panel. Might be a good one to do if you need to do replacement on the rockers due to rust.

The k Member I'm actually using is a 68 from a Coronet. Only to expedite the swap. I'll pre build it with the LCAs, strut rods, brakes, Engine/trans, etc. All the original items will go on a long pallet in tact and into storage. For that one day...
Sounds like you have done some homework on these front-ends. Good info!

 

[ckessel]

I like those 70 units. Picked one up earlier this month at the Spring Fling for $100. It's getting prepped for my 67 wagon. I also have one for my 65 that I've worked over extensively as I plan on driving that car on Autocross and track events when it's done. Project stage for now.

 

[Torkmnstr]

Def go with with bigger bars, I ran 1.03 PST units in my RR and the car handled well. I think they kept my doors closing without subframe connectors for all those years too! Lol