BB vs SB Suspension Set-ups

[Foreman72]

what are some of the key differences in parts/part strength between factory BB's and SB's? like when a factory 440 rolled out off the line what did it have for suspension parts that a 318 did?

the reason i ask is i'm trying to stay away from really expensive aftermarket suspension mods if possible and i figured the factory BB gear would cover the bases for my operation...my goal is a 400 HP 318 and thats BB power so i figured i'd put as much of the BB suspension on the car that i can...some things i'll probably go aftermarket with but cost is always an issue 

So if you have a small block making big power i'd love to hear what you have for a suspension set up...as well as the first question about BB/SB factory suspension differences...thanks a ton

[Mike DC]

 
(I'm a 2nd-gen guy, so I'm really giving you info about those cars more than the 3rd gens right now.)


The factory basically just stiffened the leaves & torsion bars and made all the brake drums an inch bigger.  That's for the R/T package.  440 or hemi. 

The 383s all still got the same equipment as the 318 cars for underpinnings except for the axle issue.  From '69 and up, the 318 cars got the 8.25" instead of the 8.75" rearend that was standard on all the auto-tranny BB cars.

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That's factory.  What YOU want is another story. 

Strictly speaking, the car will work with anything.  The only thing the big power does is get you going faster and stress the driveline harder.  If your brakes are good and the driveline isn't breaking or overheating, then you don't NEED to upgrade anything just to drive the car safely.  The only handling change that you will automatically incur with added power is when you go from SB to BB.  The bigger motor swap is 100-150lbs heavier on the front end, which makes the car want a little more spring & shock up front to get things back the way they originally were with the SB.


But I get the feeling you want to upgrade a little.


If you're not trying to optimize the whole car for straight-line drag racing launches, then I would run front torsion bars about 1 slight notch bigger than any of the stockers, and run rear springs with about 5-6 leaves.  (The stock R/T was the 6-leaf deal.  The stock 318/383 cars got 4-leaf springs.)

As for brakes, just convert to some kind of front discs.  You can keep the stock rear drums if it's not an autocross car or something.

[Foreman72]

dude thank you so much...thats like spot on what i need...so unless they're shot (which they could be, 13yrs in a dirt floor barn can do that not my choice, thats how i got it) i don't really need better front suspension parts (control arms & such) and the rear just needs a few more leaves to be set.  sweet! can i use a set of stock R/T springs if i get ahold of a set? i'm assuming they'll mate up fine to the 8.25... what about sway bars and such? obviously the parts that need replacing i'll get the next step up from stock...polyurethane bushings, new shocks...that kinda stuff...

i still don't know if i want to do anything to the stance..i just want it to sit aggressive that all... ...maybe down 2" in the front and 1" in the back...its all up the air...that where this site comes in...


but i realized its not gonna handle like a modern car but i'd like 2 beef it up a bit...what about steering components? is there anything i can do to improve the power steering i have? I don't think i can justify a R&P setup...thanks again so much...this is gonna be a huge help 

[Foreman72]

also...would i gain anything from stepping up from a 8.25 rear to 8.75?

[Charger74]

also...would i gain anything from stepping up from a 8.25 rear to 8.75?

Yeah, strength and the ability to change gear ratios easier...

[Foreman72]

would it be as simple as that? just finding and switching? is there any price difference in parts for the 2? namely Limited slips and gears

[Mike DC]

i don't really need better front suspension parts (control arms & such) and the rear just needs a few more leaves to be set.  sweet! can i use a set of stock R/T springs if i get ahold of a set? i'm assuming they'll mate up fine to the 8.25...

Don't forget the front torsion bars. 
(In case you don't realize it, the torsion bars mounted between the LCAs and the tranny crossmember are THE front springs on the car.  There are no coil springs in front.)

what about sway bars and such? obviously the parts that need replacing i'll get the next step up from stock...polyurethane bushings, new shocks...that kinda stuff...

Sway bars are good but you don't need to go overboard with them.  If you're not already running stiff-ass springs everywhere and 17-18" wheels with low-profile tires, then you won't need (or even want) the stiffest sway bars on the market.  Just get something basic for the front and rear ends.  Probably get the softest-rate rearend sway bar you can find. 


Steering boxes can be tightened with an adjustment on them.  If you want to get a rebuilt one (you probably will) then get it from Firm-Feel or somebody like that.  They sell rebuilt steering boxes with 3 degrees of firming-up.

And don't forget about the stock rag-joint between the steering box & the column.  It's a rubber part that decays over time.  If that joint is bad, then all the better steering boxes on earth won't tighten things up. 


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Poly/rubber is a long debate that's been done over and over again. 
I'm more of a fan of rubber ones, but poly has its place.  I just think poly gets overused lately.

I will make three comments about it:


1.  Remember that 40yo worn out rubber bushings are no indication of what brand new stock rubber bushings would feel like.  You don't need to switch to poly just to get anything stiffer than you currently have.

2.  There's nothing wrong with running a mixture of poly and rubber in different places. 

3.  The LCA-to-Kframe bushing is particularly important to the car.  This is the LAST bushing that I would convert to poly over stock rubber.  The metal K-frame mounting hole/tube for the LCA can sometimes start to tear out after 40 years, even with softer rubber bushings in that spot.  Check that metal area in the K-frame for cracks when you have the car apart.

[Foreman72]

thanks so much....yeah i kno what/where torsion bars are    i was looking at .940 bars from firm-feel

i was planning on going w/ 17x10's in the back and 16x8's in the front but that is very open to change. but yeah its not going to be autocrossed or anything (that i know of @ this point ) so the sways (if i got them) were going to be on the light side

i wast just under the impression that poly was longer lasting and stiffer...i guess the places that are subject to excessive wear would be the best candidates for poly...

also...

sweet! can i use a set of stock R/T springs if i get ahold of a set? i'm assuming they'll mate up fine to the 8.25...

i may be switching to a 8.75 before this is all over...so can i just grab the entire setup of the stock R/T springs w/ a 8.75 and just be good to go? i'm assuming that some R/T's had 8.75s...i could be wrong...

also...

if that spot on the k is busted what can i do to fix that...cuz i'm gonna be assuming the worst on everything until i take it apart

thanks again...

[Mike DC]

Poly is longer-lasting and stiffer. 

But that's not always good.  The factory was thinking of the impact-absorbing cushioning of the rubber when they designed the suspensions of these cars.  It's just like harsher springs & shocks:  Stiffen up the "soft" stuff, and it'll also transfer more of the load to the hard parts of the car.  The control arms, the suspension mounts, even the whole unibody's flex.  Just something to think about. 

(Remember the K-frame weakness point I brought up?  Yeah.  Poly ain't helping stuff like that.)




Poly also is prone to a squeaking problem.  Some people get this bad, others don't, some companies making poly parts make it worse than others (graphite impregnation was done into the poly to fight this), etc.  And the problem usually takes a few thousand miles to show up so bear that in mind when getting feedback on a poly setup from someone.  Ask several guys about it and you'll probably get several answers. 


The real cause of this is that polyurethane does not give in twisting directions like rubber does. 

When the modern factories use poly in certain places, they're sometimes incorporating steel sleeves into the bushing setups to take this twisting force issue into account.  But this isn't a feasible thing to do when you're talking about old musclecar restorations.  Guys like us are dealing with fitting poly bushings into the same holes that were designed for rubber bushings 40 years ago.  We don't have the luxury of redesigning the whole pivot point around the polyurethane joint like the modern factories do.


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As for the K-frame issue, the whole part isn't perfect.  Assembly-line slop just like everything else. 
Check the welds that the factory did on it, beef up where necessary.


As for the LCA mounting area, you can re-weld the factory stuff.  And/or also just weld on some thick washers as needed to beef-up the area.  An ounce of prevention is always worth a pound of cure in stuff like this.  The car lasted for 40 years the way it was, so don't get TOO worried about the whole thing.  A bit of extra strength in the area will do fine.   



The steering box mount also tends to flex some side-to-side, and it's enough to feel it at the wheel. 

But be careful about welding anything onto that left-side mass of mounts -- Between the motor mount and the motor itself being right there, the starter on it, the exhaust headers/manifolds, spark plug access, the steering box mount and all that entails . . .  there's a hell of a lot of important stuff crammed into a tiny area.  Don't weld extra bracing or gusseting crap onto anything until you know for damn sure there's adequate clearance for it.  (And don't forget that the whole motor SHAKES on its mounts when running.)



If your last name is "Duke" and you live in rural Georgia, then you probably want to beef up the passenger-side motor mount a little too.  Drop a Charger from about 5 feet out of the air, and an iron BB motor is liable to crush its stock pass-side mount upon landing.

[Foreman72]

thanks a ton...this is gonna be a huge help...i see what your saying...you can have a balance of both...its another suspension component that needs to be taken into consideration just like something as big as shocks or leaves...its a factor...

If your last name is "Duke" and you live in rural Georgia, then you probably want to beef up the passenger-side motor mount a little too.  Drop a Charger from about 5 feet out of the air, and an iron BB motor is liable to crush its stock pass-side mount upon landing.

nope thats not quite the intention haha...

what about poly mounts for engine & tranny? are they worth the extra $$? same principals apply i'd assume

[Mike DC]

Same issues apply about the poly & rubber engine mounts. 


Engine mounts don't really fail during normal usage except on hard dragstrip launches (like, hard enough to break drivetrain parts).  And if you're like most car guys, you'll probably have the motor in & out of the car often enough that there's not much need to worry about "do it once and do it right."  It takes the rubber mounts years, sometimes even decades, to wear out from weathering.  Buy you can swap them with hand wrenches any time you have the motor out. 

I dunno.  Engine mounts are another one of those areas where I wish we had a "harder rubber" option instead of having to choose either stock rubber or poly. 

It doesn't hurt to run an "interlocking" mount or just an auxilliary chain on the left side.  If torque is gonna rip out a motor mount, it's gonna be the left-side one being yanked upwards. 




(By the way, I wasn't even exaggerating about that General Lee motor mount joke.  The cars on the TV show really did often crush their motor mounts on hard landings!)

[Foreman72]

well i don't think i'll drive the motor out of the car and i certainly won't be driving off any cliffs to perform movie-quality stunts...hopefully...

but i think the rubber will do for mounting things...i'll just have to keep eyes on it...who makes good rubber bushings?

[Foreman72]

do u think this kit is overkill?

http://www.justsuspension.com/product/154

[Nacho-RT74]

This is what I know STRICTLY ABOUT SUSPENSION AND RELATED PARTS:

on suspension differences up 72 are sway bar thick, T bar thick and extra leaf on passenger side spring just for R/Ts ( 440s/Hemis )

rear sway bar for 72 rallyes

since 73 differences are

front sway bar thick, rear sway bar for rallyes, K member engine mounts position, passenger side inner fender big cut out for clearence

Notes:

T bar is not anymore a difference since 73 unless is POLICE PACKAGE EQUIPPED.

rear sway bar on rallyes ( since 72 ) is not because BB or SB since rallyes base model were 318, I'm just stating diff on suspension between models on this specific item.

[The70RT]

do u think this kit is overkill?

http://www.justsuspension.com/product/154

The link is inop? Moog makes the best rubber parts  (nascar uses them) Mancini carries Moog and so does Carquest and Advance auto.

[Foreman72]

really? it took me right there...anywyas i figured it might b more econimal if i got a kit that had what i needed instead of piecing to together...

but as it stands right now...
rear suspension
-R/T 6 leaf springs
-8 3/4 rear (w/3.55 & suregrip for what its worth, maybe i can find a rear w/ all this & the springs; wouldn't that be a catch )
-sway bar
-edelbrock or monroe shocks

front suspension
-.940 t-bars
-not sure about LCA/UCA yet...(aiming for R/T-like suspension, i don't think i'll need tubular, probably reinforced if anything)
-reinforced K-frame (if needed)
-sway bar
-edelbrock or monroe shocks

this is my plan as of right now...open to change however...

i'll also be switching to a fast pitman (planning on it) as well as 4 discs...and as was discusssed earlier, i'll use rubber and poly on various places thruout

any input would be great...thanks...can't do this alone

[The70RT]

Oh yeah....after checking more it seems that Rock Auto has the best price on MOOG parts. Carquest wants 70 bucks for 1 lower ball joint. Rock Auto 80 for two. I can't find aMOOG kit though. If anyone else knows a cheaper place let me know because I am about to spring some coin.

[Nacho-RT74]

front suspension
-.940 t-bars

on 73 and laters thats the stock T bar size, and honestly I would go higher. No less than 1" what with stiffer shock will be a better and NOTICEABLE handling profit. I went with 1.06" and got PRETTY HAPPY with them ( from firm feel, best price and service ) and still can feel I could go higher without problem, just that I'm still using the stock shocks

[Foreman72]

i ment to put .960...sorry about that...but you think i should go all the way up to 1.06? what do u have for shocks

[Nacho-RT74]

Actually I have stock gabriels, so need stiffer units to feel the diff on higway. On streets the thicker 1.06" T bars is a day and night diff, but in highways although the change is really noticeable, still bounce a little bit more I expected. I think 1.12" T bars would make a harder ride on regular street use and could it be a mistake...

Ppl is saying me KYB for stiffer shocks, but KYB doesn't offer GAS-A-JUST models for front 73 and laters, just GR2... and dunno if really is a diff between those. Was checking summit and they offer three level suitable Competition shocks.

still dunno which one to choose.

to 72 KYB offer the GAS-A-JUST models on all 4 corners.

BTW, I think 6 leafs rear springs are not really necesary for regular riding unless you will get load on trunk.

Just checked Firm Feel website and OUCH still best prices againts other manufacturers BUT they got increased more. Unless you go with Mopar Performance that are being sold on little bit lower prices at least on summit, dunno on dealers, Firm feel is still a great options.

I guess you are thinking on Mopar Performance because .96" is a MP measure

I'm not saying you must go with 1.06" I'm saying that I think no less than 1". Never will understand how factory used eigthies T bars on these cars even on A bodies. Anyway 0.96" will be a GREAT improvement too

[Foreman72]

cool...well the mopar ones are a little cheaper and this is what i was thinking for springs...
http://store.summitracing.com/partdetail.asp?autofilter=1&part=DCC%2D4452982&N=700+4294925079+4294908110+4294908099+4294925130+4294839061+400172+115&autoview=sku

but if i go w/ a just suspension package i get them all together...but firm feel's springs ae just too much...

i figure if i can get the springs used, maybe w/ a 8 3/4 then i save some cash and get a bolt up unit...who knows maybe it'll even have 3.55s and a suregrip  yeah...right...

i was looking at monroe  or edelbrock shocks...i heard some negative feedback about kyb's so i was kinda skipping them...yeah i'm pretty pumped to c how its gonna handle w/ these upgrades...course i need to get the car running first ...all in good time...