questions about rear springs on '70 Fury convertible

[PM27G0D]

Since I'm considering taking this car on a very long road trip, Route 66, I'm a little concerned about how squirrelly it is at speed. I feel pretty confident that a high speed avoidance manuver would not end well.
It's a 318, so I am thinking it probably has softer rear springs than a big block came with. The broadcast sheet for springs on my car shows "234" for both sides of the rear springs.
Does anyone have, say, a 383 '70 Fury that could check the broadcast sheet code and see what's there for rear springs?
I like things stock, but for safety, I'm willing to change the rear springs if heavier duty ones were available with other engines...plus, these are probably a little saggy just from age at this point.

 

[Wollfen]

I doubt the springs in the rear of a 383 car will be any different, you will find that heavier packs didn't get used unless you went 440 and even then maybe? I'm thinking that only 440HP cars would carry truly beefy spring packs but I am unsure. Others should be able to say.

 

[PM27G0D]

All I have to physically compare with here is this '70 318 and my '69 440hp...and there is a huge difference in the springs. I'm thinking that there must have been some options between these two extremes. The ride and handling difference in these two cars is absolutely shocking...the 440 feels and drives like a GTX, and the 70 drives and feels like the mushiest Cadillac you can imagine.

 

[polara71]

It all depends how it was ordered.....

Personally I always order 7 leaf springs from Springs and Things in Danville pa when I buy another old car. It stiffens the ride and stabilizes the car

 

[bluefury361]

Springs are built to support the vehicles weight primarily. If control issues are your main concern you need to look into stiffer shocks and perhaps an anti sway bar.

 

[70NPORT]

I went with the seven leaf setup also. Getting ready to attach it in a few days.

 

[PM27G0D]

I guess it's possible that the new tires and shocks I haven't installed yet, will improve it enough to satisfy my safety concerns, and perhaps not have to get into modifying anything. I don't want to autocross this thing...just want a less squirrelly feeling at highway speeds. Part of my queasiness about it probably comes from the direct comparison of this car and the '69 440 Fury...of which there are several orders of magnitude in the way they handle.

 

[PM27G0D]

I took this pic of a spring on the 70 yesterday. Looks like a 5 leaf, and appears to have little, if any, arc to it. There is no additional weight in the car now. Does this look normal?

 

[polara71]

Yes, for a 45 year old spring..

If it were new? No.

I disagree with Will on this one. .... The springs have plenty to do with stability.

 

[PM27G0D]

Yes, for a 45 year old spring..

If it were new? No.

I disagree with Will on this one. .... The springs have plenty to do with stability.

Considering that the springs and torsion bars are the basic difference between this car and my incredibly good handling 69 Fury...I'd say so as well.

 

[68plymouth383]

The 69 fury, and your 70 fury use the same length, width, and locating pin spot as your 70 does. The best thing to do is if you like how the 69 rides order that amount of springs for the 70. Yes shocks play a role in dampening but they don't control body roll, and sway.

 

[PM27G0D]

I'm looking for something inbetween the two cars as far as springs. I haven't looked closely, but I suspect the '69 has 7 leaf springs...probably the stiffest available in '69. Surely, there was something available in '70 between these little 5 leaf ones and the monsters on the '69.

Heck, I'll go out there and take a pic of the '69 springs...that should clear that up!

 

[polara71]

So order six leaf stock height.... done deal.

I think I read this is an over the road cruiser....take into consideration luggage and cooler weight in the trunk.
To me five leaf is too soft , while 7 may be tight it doesn't bother me one bit, it's not like it hops like fully blown air shocks

 

[polara71]

Considering that the springs and torsion bars are the basic difference between this car and my incredibly good handling 69 Fury...I'd say so as well.

You have wider tires on your 69 correct? Sway bar? Weight of the BB versus the SB is all playing a part. How's your frond end components on the rag? Steering box? Your 69 has 9000 miles and is a hard top.... no comparison for the defenseless convertible

 

[PM27G0D]

springs on the '69...

 

[PM27G0D]

So order six leaf stock height.... done deal.

I think I read this is an over the road cruiser....take into consideration luggage and cooler weight in the trunk.
To me five leaf is too soft , while 7 may be tight it doesn't bother me one bit, it's not like it hops like fully blown air shocks

Yes, on the Route 66 trip, I'll have a pretty full trunk...with luggage and camera stuff.

 

[polara71]

Consider that. I always replace the springs on an old car when I purchase it. To me it's the biggest, simplest suspension upgrade. I personally like a raked stance so they all go 1" over stock height. Once I put a couple teens in the back seat,luggage and a cooler on the way to the beach it levels out quite a bit.
And it will settle in. It may take longer than you like but it will

 

[PM27G0D]

You have wider tires on your 69 correct? Sway bar? Weight of the BB versus the SB is all playing a part. How's your frond end components on the rag? Steering box? Your 69 has 9000 miles and is a hard top.... no comparison for the defenseless convertible

Yes, the '69 has 8.55x15s and the '70 has 8.00x15s...although soon to have P215/75R15 tires. Front end "feels" tight on the '70, comparable to the '69...no wandering, but the power steering could be masking some wear. Plan to check the front end before alignment.
I think my main issue is the tremendous body roll it has...likely a combination of all these factors adding in the wrong direction. The normal expected body flex of convertibles really isn't noticeable in this car, like it has been in previous non-Chrysler convertibles I've driven. The body feels really tight.

 

[polara71]

There is four large teens in this one with 10 year old springs

 

[PM27G0D]

View attachment 51133

There is four large teens in this one with 10 year old springs

Did you go with six...or seven leaf springs...and where did you get them from? I've never replaced springs on any of my cars as most of them have really heavy duty ones that seem to hold up pretty well, and...they have no handling issues.