Small block to big block...

[Tilar]

My 68 originally came with a 318. It had a 400 in it when I bought it. I'm going to put a 440 in it.

As far as the front suspension is concerned, What should I change to make it ready for the extra weight? What if anything was different between the small block and the big block? I'm for sure going to go with some sort of disc brake setup instead of the drums.

[Chatt69chgr]

Bigger torsion bars.  Book lists the .92 inch as std.  I went with .96.  Both available from Summit Racing.  May want to go to bigger front sway bar.  Firm Feel has one.  I think Addco did have one.  Lots of info on here about brakes.  Calipers need 15 inch wheels.  Disc's used a hold-off valve.  Inline tube has.

[Mike DC]

The only factory-built differences were between the R/Ts (440 or 426) and non-R/Ts (383 or 318).  The R/Ts got the 0.92 torsion bars instead of the stock 0.90 bars in the 383 and 318 Chargers. 

Do a search, there's tons of torsion bar discussions in the past.  The general consensus (even from Mopar itself these days) is that the stock torsion bar rates were a bit low.   


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The factory also gave the R/T cars all 11" drums instead of 10" drums on the 318 and 383 cars.  Although for some reason if you ordered any car with the factory optional front discs, the car kept the 10" rear drums even if it was an R/T car. (R/Ts normally would have been slated for 11" rear drums along with the 11" front drums as standard equipment otherwise.)


You're right about the discs.  On a fun street cruiser, the brakes really need to be discs at least in front.  You don't need the greatest discs on the planet just to make a safe street cruiser, but get SOME KIND of discs instead of drums on the front end.  (Front discs were becoming standard equipment on cars of this size/weight within a decade after our cars were built.  What a challenge - we update our street cruisers to 1970s standards of safety.)

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In terms of handling, the general feeling is that the stock front torsion bars were a bit too soft even on the R/T cars.  The sway bars were all too soft too.  None of the stock rates were WAY off, but the better modern tires tend to make you want almost everything at least a little bit stiffer than it came from the factory.


Spring/sway/shock rates are a whole issue unto themselves.  A LOT depends on what you're wanting to do with the car. 

[Tilar]

Bigger torsion bars.  Book lists the .92 inch as std.  I went with .96.  Both available from Summit Racing.  May want to go to bigger front sway bar.  Firm Feel has one.  I think Addco did have one.  Lots of info on here about brakes.  Calipers need 15 inch wheels.  Disc's used a hold-off valve.  Inline tube has.

Do I need to change the lower control arms or anything else when I go to larger torsion bars?

You're right about the discs.  On a fun street cruiser, the brakes really need to be discs at least in front.  You don't need the greatest discs on the planet just to make a safe street cruiser, but get SOME KIND of discs instead of drums on the front end.  (Front discs were becoming standard equipment on cars of this size/weight within a decade after our cars were built.  What a challenge - we update our street cruisers to 1970s standards of safety.)

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In terms of handling, the general feeling is that the stock front torsion bars were a bit too soft even on the R/T cars.  The sway bars were all too soft too.  None of the stock rates were WAY off, but the better modern tires tend to make you want almost everything at least a little bit stiffer than it came from the factory.


Spring/sway/shock rates are a whole issue unto themselves.  A LOT depends on what you're wanting to do with the car. 

Yeah, that's ironic that updating to a safety standard that is 35 years old is better than what we had.

Really all I want is like you said, a fun street cruiser, but on the same note if I mash the pedal to the floor I want it to have a real good understanding of what I'm wanting to do. 

[Tilar]

Oh, and Cody brought up something in another thread here that reminded me of something else I want/need to know... Are sub frame connectors/Torque boxes and frame rail connectors going to help that much? In my mind they would since it's a unibody, and I don't mind spending the money to add them if they will, so anything along those lines that I should consider would be good to know.

And what about these?

http://cgi.ebay.com/ebaymotors/1968-1969-1970-HEMI-DODGE-CHARGER-Reinforcement-Kit_W0QQcmdZViewItemQQ_trkparmsZ72Q3a727Q7c66Q3a2Q7c65Q3a12Q7c39Q3a1Q7c240Q3a1318Q7c301Q3a0Q7c293Q3a1Q7c294Q3a50QQ_trksidZp3286Q2ec0Q2em14QQhashZitem130277850359QQitemZ130277850359QQptZOtherQ5fVehicleQ5fParts

[Mike DC]

 
As for the parts in the Ebay ad, they aren't a bad idea but they're probably not a necessity unless the car sees a lot of hard dragstrip launches. 


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As for unibody stiffening, yeah I say do it all.  These cars were on the verge of buckling their quarter skins right from the factory, let alone now with 40 years & a bunch of modifications on them.  Even if you never lean the body that far on cornering, The car will ride better on bumps and generally feel tighter.  (As long as you're not doing a full-stock resto and as long as you don't hack the floors for the subframe connectors, then the stiffening mods are pretty mild.  It's welding, but it's nothing too irreversible.  Just a bunch of adding metal onto the stock unibody, not cutting things off.)


XV Motorsports just did nice & professional pile of new research on B/E-bodies to figure out what really works and what doesn't.  Their conclusion was:  Add factory-style torque boxes, decent normal subframe connectors, they did their own design of front lower rad brace, and their own shock tower braces.


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And BTW, the lower control arms don't need to be replaced just for a torsion bar swap. 

You might wanna replace the UCAs with aftermarket ones just for caster alignment reasons.  But replacing the original upper & lower control arms isn't inherently necessary for any reason.  Check for cracks & bends and re-use. 



But while you've got the front suspension apart, check the LCA's mounting tubes that are built into the K-frame.  This area is prone to metal fatigue.  It's good to gusset them with a little extra welding/plating even if they're not visibly tearing out. 


The factory steering box mount on the K-frame can flex from side-to side in stock form too.  That's steering slop. 

[Tilar]

I'll definitely add the extras then. As far as the UPA's I thought the original uppers would allow you to adjust the caster. I used to do alignments back in the mid 70's but I can't remember having any issues with the B-bodies.

I don't plan on doing any hard dragstrip launches but I may run it down the strip once or twice just to say I did and to see what numbers it will do. I would like to see some pics of those plates on ebay after they've been welded. I'm not sure where they're supposed to go.  I can beef up the K-Frame in those places easy enough.

Thanks a lot for the info! 

[Chatt69chgr]

Since you are planning to stiffen up the suspension and body, you might want to condsider these LCA plates:

http://www.arengineering.com/suspension/lca/lca.html

Also, I think there is a Moog bushing kit for the control arm that does allow some adjustment---don't if it's the UCA or LCA.

Finally, look at the Borgeson U-joint that replaces the factory steering box to steering shaft connection.  Many say that this really tightens up the steering over what you would get just rebuilding the factory connector.

[Mike DC]

     
The stock UCAs do allow some caster adjustment, just not nearly enough for the average resto-mod Charger nowadays. 

Moog also sells an offest bushing option for the Mopar UCAs.  It's a band-aid and not really a huge gain, but it's a very cheap & easy way to help the situation a bit.


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The factory designed the suspension while assuming they would sell a lot of cars with manual steering.  So the factory design was way under-castered to make them easier to park.  It still gained a bunch of caster on compression (probably mostly for anti-brake-dive reasons), but I think the original intended static caster setting at ride height was literally zero. 

Furthermore, most of us nowadays rake the stance of the car at least a little bit more than stock.  That works against the caster we want.  (If you're trying to make sense of this, think about how raking the stance also puts the headlights pointing too far down.)


The fact that we tend to run the front end cranked down a little from true-stock also affects the camber.  It adds negative camber in the static position since the front end of the car is now sitting in a slightly compressed position relative to the original factory setting.  But this is basically an accidental improvement for us now, because modern radial tires tend to like a couple degrees more negative camber than the original bias-plys did. 



Bottom line - you probably want a set of UCAs with the caster moved a good several degrees farther backwards, but the camber unchanged from stock.

[Tilar]

Chatt69chgr - I've seen those plates and like the idea behind them. I'll more than likely add those. I'll take a look at the Borgeson joint.

Mike - I've thought about keeping the front end just a little lower than stock anyway so thats good info to have. When I get to the point of actually buying specific parts, I'll more than likely ask for some more advice on that once I get to that point.

[Mike DC]

Good to go.

Most of the hobby runs these cars with the front ends at least a little lower than stock.  It's so common that the stock height is the one that looks funnier to most of us now. 

Look at the advertising for these cars when they were new, and check out where the center point of the front wheel is relative to the bottom of the rocker panels.  Those things originally sat higher up than most of them do now for sure.

[Tilar]

Now that you mention it, some of the old videos do look like they've been raised up a notch.

I remember back, I think it was 1978, I was working for a Kelly Springfield Tire center in Tyler Texas. I was the brake and front end man. Anyway, a couple young boys came in with a 69 charger, and for some reason they wanted me to run the bolts down on the torsion bars and raise the front end way up. I told them that if i did that I couldn't align the front end right and it would ride like a log wagon. The kid that owned the car said he didn't care and he wanted the front end raised, so I torqued them most of the way down and tried to find a happy medium between not wearing the tires real bad and still be able to hold it on the road.

He came back an hour later wanting another front end alignment. 

[Mike DC]

High up front ends (and rear ends) was the syle for a while in the 1970s, just like the "bling & dubs" guys do now.


If you watch "Dukes of Hazzard" much, you can notice that the show's car mechanics monkeyed with torsion bar adjustments all the time.  They jacked up the front ends to clear the takeoff ramps better on some cars, and lowered the front ends to handle & oversteer better on others. 

 

[firefighter3931]

Here's my 


The stock suspension components are plenty strong.....lots of guys race with stock stuff. In your case a torsion bar upgrade, lower control arm plates and a fresh rebuild of the tie rods, ball joints, bushings etc... should be sufficient. I like Poly stuff for the firm feel that that just feels right. Good shocks make a huge difference as well. 

Subframe connecters are highly recommended....i won't run any unibody without them. Add a rear swaybar and some descent leafs out back and you're good to go.



Ron

[Tilar]

There is a chart on this page. I'm thinking maybe the 1.0 diameter bar. What is the "Rate" column referring to?

[doctorpimp]

Not sure about the rate... Call FFI, they are good people and can help you out in regards to front-end and steering parts and questions

I do have a brand new set of Mopar Perf 0.96 torsion bars for sale.  PM me if you're interested.

[mopar_nut_440_6]

Since you are planning to stiffen up the suspension and body, you might want to condsider these LCA plates:

http://www.arengineering.com/suspension/lca/lca.html

Also, I think there is a Moog bushing kit for the control arm that does allow some adjustment---don't if it's the UCA or LCA.

Finally, look at the Borgeson U-joint that replaces the factory steering box to steering shaft connection.  Many say that this really tightens up the steering over what you would get just rebuilding the factory connector.

How big a difference do these make? I have never had any issues with a LCA in a b Body but would not be resistant to this if there were noticeable benefits!