68 Road Runner

[Maxwedge]

I have a 1968 road Runner that is very close to being complete after a 3 year restoration.
My problem with the car is that I cannot keep the rear BEHIND the car.
The Motor is a fairly stock, but completly rebuilt 383. All new pistons and valvetrain,
electronic ignition, Holly carb and a single plne Intake. I have super stock springs, and rebuild the entire suspension with poly urathane bushings. I also have front and rear swaybars on it. the rear swaybar came from a 72 charger.
The tranny has been completly rebuilt and a a B+M Shiftkit installed. It also has a new 2800 rpm stall speed converter.
anyway I have huge Micky Tompsons on the back, I dont remember the size off the top of my head BUT they fill the wheel wells quite nicly.
The rearend gears are 3.91 posi set.
I think the rear might be too high, maybe? and I also (this will be a shock to you all)
Please help had to replace ALL the rear sheet metal. I bought all paddok parts and the metal seemed to be of a good gauge. But the rearend is probably very light.
anyway any help has to be appreciated.
Maxwedge

[Elwenil]

The problem you are having hooking up and going straight is probably the fact that you suspension might be too stiff. The first thing that comes to mind is the rear sway bar used with S/S springs. One cancels out the other in my mind. Try unhooking the sway bar and installing an adjustable pinion snubber, with about 1" clearance from the floor pan. You probably will bottom out all the time with only 1" of rear travel, but that is why it's adjustable. You didn't say what kind of shocks you have, but if you have a rear sway bar, I'm guessing that you went with a H/D or high performance shock. For a street/strip car, I have found that just cheapo shocks work pretty good. Not so soft to make the car ride bad, but not so stiff as to keep the suspension from transfering the weight to the rear. I know the popular thing to do to fit tires is to use air shocks, but if you have these, you don't have a lot of hope hooking up. Remember, if you are looking for traction, the width of the tire is more important than height. This may not be the case for a strip car, but on the street, wide with a normal height works better to keep from having to jack up the rear. I run BFG Radial T/A's on my Charger in a P295/50R15 and they fit nicely and are about 11" wide. Radial T/A's aren't the best thing for traction, but you get the idea about the sizing. Normally good tires, S/S springs and a pinion snubber are the recipe for traction in just about any Mopar, but the sway bars really hurt you in the launch area. Hope this helps some. Anyone else?

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~Elwenil~ ~.\|/.~

[DartGT66]

If traction during acceleration is the problem the rear sway bar shouldn't hurt it, on the contrary. They are used even by some Stock racers. I would think that you have too much power for the tires. The widest tires aren't always the ones with the best traction, bad tires will not hold even with a four link. Try some other brand tires first, and if that is a a major problem go to McCrearys, M&H's, Hoosier pros or M/T ET streets. I bet your traction problems will end up to that point.

[JCNathan]

Elwenil is correct. My experience with super stock springs on a basic "stock" car was the same as Maxwedge. I'd go back to the stock springs, use the sway bar, pinion snubber, and good quality gas shocks. This setup worked on my 64 Fury, 383, E/SA.

[Maxwedge]

I have already dont the rear sway bar thing, running with and without it, it didnt seem to matter, the rear suspention is WAYYYY stiff as had been suggested and I have a new pinion snubber on it, and after checking the thing was closer than 1 inch so I will change that. the tires are also kinda old(5 years) because I have been collecting good parts for this car for awhile, and the tire compound on the good years isnt so soft. that is probably, as suggested, another issue..
anyone else??

[Christopher]

I have the S/S springs on my 70 Road Runner.It's a 4-speed,and if I really drop the clutch,it will spin the street tires bad.Now when I have the M&H's on,if I clean the tires and then dump it,it won't spin.I think the tires are the problem.

[Maxwedge]

I am reading in an older(aka mid 80's) Magazine about how Dick Landy set op this 69 roadrunner. And one of the tips he suggests to get a better bit of traction is to get the SS springs and modify the forward spring perches so that the springs eye hole is level with the floor of the car. He said he usually moves the forward spring mount a full inch up.
anyone have any experience with this or read anything else similar??
and thanks for the previouse responces.
Maxwedge

[Maxwedge]

I am reading in an older(aka mid 80's) Magazine about how Dick Landy set op this 69 roadrunner. And one of the tips he suggests to get a better bit of traction is to get the SS springs and modify the forward spring perches so that the springs eye hole is level with the floor of the car. He said he usually moves the forward spring mount a full inch up.
anyone have any experience with this or read anything else similar??
and thanks for the previouse responces.
Maxwedge

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[Elwenil]

Hey, an easy way to lower the rear of a Mopar and increase traction is to just flip the front spring mount upside down. You will have to take a hole file and widen the holes a bit, since they are spaced differently on top and bottom. There was an article on this in High Performance Mopar magazine (I think) called Attitude Adjustment several years ago. I think it lowered the rear about 1 1/2". A simple trick to give you Mopar that low and mean look!

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~Elwenil~ ~.\|/.~