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View Full Version : 1968 roadrunner question on rear setup


nazar
12-12-2005, 01:04 PM
I am going to start working on a 1968 roadrunner 383 car and had a question

Look at this website www.hotrod.com and look at the header, there is a creme roadrunner with some badass black wheels, sitting low

My question was on the rear end and tubbing it. DOes that car appeared to be tubbed? And if so, how do i figure out how much to tub it, and how to go about it? Do i just buy a rear end thats shorter? What happens to the rest of the suspension, do i have to relocate it??

I dont want a huge tub like those drag cars, just enough to clear say a 18x12 wheel in the rear. The fronts I am going to convert to a PTE coilover suspension with tubular control arms, however I have no idea how to go about the rear, but that car looks AMAZING and is exactly what direction I am going in.

ALso, as a bonus, does anyone know what wheels those are? I cant quiet tell

I want the rear to tuck and I know a wheel that big wont, I think the most you can stick under there is like a 9.5 wheel on a 275

I want a 12" wheel on 335s or so.

Thanks guys, cant wait to start working on it, my first project, im 22 :thumbsup: Ive been in the import scene for a while building up my 2nd car, 99 eclipse gst with a fuly built motor making 420whp and complete suspension/wheel/tire/trany work but i have always wanted to build a badass hotrod, modern style that handles and goes

nazar
12-12-2005, 01:36 PM
also does anyone know any good suspesion/drive train websites that sell mopar parts? PTE makes a front suspension kit with all new bushingsjoints/control arm/torsion bar or coilovers

I need to address the rear suspension and rearend

THe motor I am just going to buildup the 383 already in it, its healthy and already has a big cam

Mopar magazine made 460hp on a stock 383 with cam, headers, intake manifold and a demon carb..thats plenty, that with some nitrous is the way I am going to go to stay on a budget

TravisB
12-12-2005, 02:44 PM
I believe that is a car called the Hammer built by Steve Strope. To minitub the rear we usually order the wheels I want with BS(back spacing) I want then cut the wheel tubs out until they fit build new wheel wells and then take a measurment and order a new rear diff or have the existing one shortened. A modification like this will require some suspension modifications as far as mounting pionts etc etc

XcYZ
12-12-2005, 02:49 PM
Welcome Nazar. We need more Mopars and your project sounds great.

The process that Travis mentioned for the rear suspension is definitely the way to go. For the other questions, unfortunately, I'm not up on Mopars. I'm sure others here can give some insight.

nazar
12-12-2005, 04:10 PM
Well, I think for a tire that wide the axle will have to be shortened.

I am assuming it has the 8 1/4" rearend in it, which if it does, I will keep it and just beef up the internals. I think the less powerful mopars came with the 7..." rear end, and the real beasts had the 8 3/4". I will just rebuild it and put a mopar diff into it along with gears.

The tranny is a 727 3 speed auto...is this a decent tranny to keep for a while and just put a shift kit in it and possibly a basic rebuild? I dont want to spend the extra money on a new badass tranny just yet, wanna get the car running well and rolling and some other stuff done first, if it aint broke, I dont wanna completely fix it just yet.

I will most likely need a leaf relocation kit, I will keep the leafs in the rear, add some traction bits, shocks, subframe connectors, and possibly a coilover kit in the front.

But for now I want to figure out the rear suspension and how to get a 18x12" wheel on a 335tire out back. The front I will do a 17x9" wheel, 275 tire if it fits.

I want to get a complete rolling chassis going and complete. The frame has been already taken off and powdercoated!! which is great. The body is straight because a body shop used to own it, they cut out the rust spots and its all in pretty good shape, ready to sand and paint.

TravisB
12-12-2005, 04:34 PM
I think competition engineering makes leaf relocators.....moser could be probably help with narrowing the axle. What wheels are you wanting to go with?

nazar
12-12-2005, 04:46 PM
thinking either kinesis or hre, some sort of clean, multispoke, polished lip, flat black spokes.

18x12 out back, 17x9 or so up front, ideally a 335 out back, 275 up front. I would love to go with a whole new front end kit with the new k member and all, but htats upwards of $4k...I think i will keep the stock one for now, and just do the coilover conversion as well as all new bushings/tie rods and tubular control arms.

I wonder if the fronts will clear as well?

Also, does anyone make specific 4 link for the rear? Or are they somewhat universal? I have access to all the tools in the world, welders, plasma cutters, steel, etc....so custom fabing up little things here and there aren't a huge problem

TravisB
12-12-2005, 05:01 PM
none that I know of for a mopar.......fabbibg one shouldn't be too hard there are several parrallel 4 links that are universal.....the one from air ridetech comes to mind i'm sure others will have some options as well

Mean 69
12-12-2005, 05:46 PM
We just bought a B-Body car for development purposes, and are basically begining the development of a three link kit derived largely from our F body. I expect to have a prototype in a couple of weeks, we committed to a customer that is doing a buildup for one of the larger supply houses, his car will be debuted in the March timeframe. Our car is a 1968 Satellite, and frankly is our first Mopar. I am super excited about the car, and from a cursory glance, it looks like there is TEMENDOUS room for improvement, both in the rear suspension, but more so in the front. We are working with the same customer on his next project, to do a full on front setup too. Anyway, I hope to have a rear kit out by the end of January, and the front stuff will likely be several months after that due to the relative complexity. Our website is still under construction, but if you are interested, you can shoot me a PM and I can send some photos over to you of our current kits, it will give you a good idea of what the Mopar setup will be like.

It looks to me that a 315 tire will potentially fit in the rear with a bit of modification to the inner fenderwell, there is a pretty significant space between the quarter and the inner, so our plan is to move the fenderwell outwards. I am hoping to get a 315 in the car without tubbing it. If I can't, well, then we'll be tubbing the car, and probably going bigger. It also looks like there is enough room in the front for a 275 as you stated, so it should look really mean. It is not so obvious about fitting a 335 back there, not without a tub deal, but it won't need much relative to other muscle cars in order to make it happen.

I was blown away to learn that the B-body cars are unibody. I already have a concept for a subframe connector, it should be simple to make out of 2.5" square tubing.

Cool cars, I am super excited to learn more about them and to work with other folks who love the cars. There is so little out there, I think we can help out a ton.

Mark

Hooligan
12-12-2005, 05:53 PM
Nazar The car as mentioned above is Hammer the wheels are kinesis.

The stock rear end was either a mopar 8.5 or a dana 60. I know for a fact that you can fit 15x11 inch wheels in the back without tubbing, but that doesn't really help you all that much.

nazar
12-12-2005, 05:55 PM
cool beans, definetly keep me updated on the progress

I will be making my own subframe conectors, going to do something different looking, perhaps X them instead of just parrallel

Offset of the wheels will play a big role in the front to get it to fit and unfortunately there is no prior tests of it so I am not sure how to go about picking the right wheel to fit a 275 up front

THe rear i want a 335 so I think I will mini tub it, shouldnt be too bad, just shorten the rear end a bit.

What is the advantage/disadvantage of a 3 link vs a 4 link?

Let me know, I will definetly be ordering one.

As far as the front, i wouldnt mind a clean kit that keeps the stock frame for now, i dont want to spend too much money on a whole new front k member setup

Post some pics of your 68 you guys are working on

nazar
12-12-2005, 05:56 PM
Nazar The car as mentioned above is Hammer the wheels are kinesis.

The stock rear end was either a mopar 8.5 or a dana 60. I know for a fact that you can fit 15x11 inch wheels in the back without tubbing, but that doesn't really help you all that much.


really? I heard guys barely fitting 275s on 9" wheels, so how will an 11" fit?

I just read up the specs on the hammer. It says the rear has a mopar spring relocation kit but doesnt mention anything about a narrowed rear end, maybe just moving the leafs is enough? I cant imagine that, especially since they used a 19x13"

nazar
12-12-2005, 06:56 PM
I need a way to find out the wheel specs(offset and backspacing) on that hammer car, supposedly they didnt narrow the rear end and have a 13" wide wheel on there

I think offset and backspacing is key because the mopar leaf relocator moves the leafs in 3" on each side, that should clear up alot of space, and I can always cut the wheel well out and modify it...if I dont have to shorten the rear end, I dont want to...I'd love to stick a 18x12 back there on a thick tire, the car is so long and big that it needs a big tire to somewhat put it back in scale

Hooligan
12-12-2005, 07:43 PM
Ok mine are 275/60R15's on 9 inch rims with a few inches(3.5 fingers, very scientific) to spare, but now that I think about it the trunk has been replaced and I'm the 3rd or 4th owner doh :_paranoid. It probably has had a little more work done to it than I knew about.:unibrow:

nazar
12-13-2005, 12:09 AM
i think with a custom wheel i can get any backspacing i want, as long as i can create clearence inside the car, lol....so i dont have to cut the axle down....just pick the right offset and backspacing, probably will need about 6.5" of backspacing or so...I really want that wide 12" wheel look with a wide tire cause its such a huge car

I am thinking now of the CCW classics, 17x12 out back, 17x9 out front

nazar
12-13-2005, 12:14 PM
Ok guys, just found out it has the 8 3/4" rear end swapped over from the hemi and also has power drums all around

The rear end I am excited about, too bad parts for it are pricey, and its gonna need a diff to get both tires to lock

But at least its beefy

USAZR1
12-13-2005, 05:18 PM
Hemi Roadrunners came standard with a Dana 60. The standard rear in a 68 RR would be an 8 3/4.
An 18x10 wheel with 295/40 tire will fit easily on the rear. That extra 1.5" of tire width (295 vs 335) is gonna cost a bunch.

nazar
12-13-2005, 05:45 PM
Hemi Roadrunners came standard with a Dana 60. The standard rear in a 68 RR would be an 8 3/4.
An 18x10 wheel with 295/40 tire will fit easily on the rear. That extra 1.5" of tire width (295 vs 335) is gonna cost a bunch.


are you assuming htat 18x10 fit with the leaf spring relocator? Because im goin to get the mopar 3" leaf relocator? or are you talking about the inner fender? I was lookin at it, seems prety hard and thick if i had to cut it, but seems like theres tons of space if u move the leafs in more

I was hoping for at least a 11-12" wheel. I will get the wheels built in a way that totally maximizes offset and backspacing so it comes right out to the fender and goes all the way in as far as possible inside

The car also has power booster drum brakes all around and the upgraded sway bar option from the factory

Needs new interior, windows, paint, some exterior bits, not bad for the deal i got, the engine has been rebuilt and is very fresh with a denominator manifold, big cam and rebuilt carb, but needs fuel lines cause 1 is leaking i think

DRJDVM's '69
12-13-2005, 07:09 PM
I just bought a '70 Barracuda, which si the first Mopar for me too, so I'm in the same boat as you. I have no idea what the "tried and true" info is about backspacing and rim/tire size etc etc.

When I did my '69 Camaro, there was gobs and gobs of info about what backspacing and rim/tire size would fit a 1st gen. It was easy to find out. This car is going to be a bit trickier to make sure I get stuff that will work.

nazar
12-13-2005, 11:06 PM
I just bought a '70 Barracuda, which si the first Mopar for me too, so I'm in the same boat as you. I have no idea what the "tried and true" info is about backspacing and rim/tire size etc etc.

When I did my '69 Camaro, there was gobs and gobs of info about what backspacing and rim/tire size would fit a 1st gen. It was easy to find out. This car is going to be a bit trickier to make sure I get stuff that will work.

the wheel deal is quiet simple

You can do all the measurements on the car to get the exact offset and backspacing you can do

Most upper scale wheel manufacturers offer detailed instructions on how to do so and get the exact wheel to look just like you want

I pretty much want to maximize all the space in the fender, from the outside to the inside fender, as much as i can and as wide as i can, because its a huge car and it needs wide tires to even it all out

70Dustpan
12-18-2005, 03:53 PM
With the springs moved under the frame rails and the tubs widen to the frame ( mini tubbed ) you can fit 15X12's with 29.5X15.5. This is what is on my buddy's 68 Sat.
As for a good handling frontend on the cheap I would go with larger T-bars, tubular upper control arms, adjustable strut rods, box the lower control arms, and some good shocks.
For brakes there are many kits out there for 4 wheel disc set-ups.

nazar
12-18-2005, 08:51 PM
thanks


for the front im goin to stay cheaper for now, like you said and pass on the coilover for now

I will do 1.2 torsion bars, some shocks(bilstein if i can find them) tubular control arms, complete polygraphite bushing kit, sway bar links(it already has a sway bar, may go larger), box the lower control arm, adjustable strut rods and weld up as much as i can of the rest of the frame.

The rear I am not sure, i could relocate the leafs, but after i spend money on that, new leafs, and shocks, I might as well do a 4 link and just some basic coilovers. I mean a 4 link will cost me about $300 and my own fabrication and welding, some coilovers another $350 or so and a side - side link to keep it from moving....plus that would give me even more room. So im not sure yet

nazar
12-19-2005, 02:41 AM
We just bought a B-Body car for development purposes, and are basically begining the development of a three link kit derived largely from our F body. I expect to have a prototype in a couple of weeks, we committed to a customer that is doing a buildup for one of the larger supply houses, his car will be debuted in the March timeframe. Our car is a 1968 Satellite, and frankly is our first Mopar. I am super excited about the car, and from a cursory glance, it looks like there is TEMENDOUS room for improvement, both in the rear suspension, but more so in the front. We are working with the same customer on his next project, to do a full on front setup too. Anyway, I hope to have a rear kit out by the end of January, and the front stuff will likely be several months after that due to the relative complexity. Our website is still under construction, but if you are interested, you can shoot me a PM and I can send some photos over to you of our current kits, it will give you a good idea of what the Mopar setup will be like.

It looks to me that a 315 tire will potentially fit in the rear with a bit of modification to the inner fenderwell, there is a pretty significant space between the quarter and the inner, so our plan is to move the fenderwell outwards. I am hoping to get a 315 in the car without tubbing it. If I can't, well, then we'll be tubbing the car, and probably going bigger. It also looks like there is enough room in the front for a 275 as you stated, so it should look really mean. It is not so obvious about fitting a 335 back there, not without a tub deal, but it won't need much relative to other muscle cars in order to make it happen.

I was blown away to learn that the B-body cars are unibody. I already have a concept for a subframe connector, it should be simple to make out of 2.5" square tubing.

Cool cars, I am super excited to learn more about them and to work with other folks who love the cars. There is so little out there, I think we can help out a ton.

Mark

please send me the pictures, [email protected]

I decided on a 295/35/18 on a 18x10 wheel that i am about to order

I dont want to go to a tub deal and cut up the car just yet

I was thinking about a mopar leaf relocator, but after the hassle, the cost(new leafs, relocator kit, shocks, some sort of wheelhop/bind device...traction bar, slide a link, etc) I will be almost at the cost of just a plain ol 4 link and coilovers

I mean I can get any 4 link and just weld it up, throw some qa1 coilovers on it and call it a day right????

The front i think i'll stay with the torsion bars for now till i see something i like

the front will also get 18x8 wheels on probably a 255/40/18 tire

Datsbad
12-29-2005, 11:30 PM
I know for a fact that the "Hammer" was what they call maxi tubbed. LOL! Leaf relocators and a custom rear leaf spring. Also the hammers wheels were in the 7,000 range .

Get us some pics of that car . I am itching to do a Mopar bad !!!

eric36
11-29-2010, 11:46 PM
Any updates on the car?