440 '48 Plymouth Coupe

[SuperBuickGuy]

Most the straight axles I've done I put shackles in the front and had no issues. I put them in the rear on the Austin simply because the stock axle had them in the rear and I was able to reuse the stock mounting point and fab new in the front. It works just as well as the others I've done. Not sure there is a better way, as I see most factory setups have front shackles.

Chevrolet trucks have the reverse. It's a choice, but given a preference, I'd always put them in the back.... of course, how arched the spring makes a huge difference. On my landcruisers, the difference was above 60 mph - of course, a stock land cruiser (FJ40) can't do 60 - but the difference was substantial. With the shackle on the front, the distance from the front of the spring to the axle can change. That change, in essence, changes your wheelbase on one side only - thus your car goes the direction of the spring that has the most deflection. On a smooth dragstrip, it should never make a difference, but on streets - it really can get to be a handful, especially if you have a super short wheelbase. In short, you got lucky my friend

A lot of people leave the front shackle because you can do a shackle lift on the front without causing terrible driveshaft angles. Because most shackles are made of stronger steel and boxed, you actually get better handling then before.... still, the shackle should always be to the back.

[1946Austin]

Most the straight axles I've done I put shackles in the front and had no issues. I put them in the rear on the Austin simply because the stock axle had them in the rear and I was able to reuse the stock mounting point and fab new in the front. It works just as well as the others I've done. Not sure there is a better way, as I see most factory setups have front shackles.

[STINEY]

In the 90's a shackle relocation kit was quite popular for the CJ's and YJ's, improved the ride a BUNCH.

Still, having put 100,000 miles on my '86 CJ7, it wasn't too bad in original configuration. Stiffer springs made it unbearable, it danced on every bump.

[SuperBuickGuy]

Thanks! I expect it'll drop down a bit but not a whole lot - I've only got a couple of leaves in the springs at the moment and will be putting the rest back in when the car is fully assembled.

As for shackles on the front, I think the majority of gasser style cars are like that although I've also seen plenty with the shackles at the back. Don't know if one's better than the other but my '47 had the shackles at the front and drove great so I've done the same on this one.

and jeeps have as well (shackles in the front). anyway, it's merely something to consider

[racingsnake440]

Nice stance! Hope it stays up in front once the engine weight is sitting on it!

Thanks! I expect it'll drop down a bit but not a whole lot - I've only got a couple of leaves in the springs at the moment and will be putting the rest back in when the car is fully assembled.

As for shackles on the front, I think the majority of gasser style cars are like that although I've also seen plenty with the shackles at the back. Don't know if one's better than the other but my '47 had the shackles at the front and drove great so I've done the same on this one.

[SuperBuickGuy]

out of curiosity mostly - I've done better then a dozen FJ40 landcruisers, and my 1st fix was moving the shackles to the rear of the spring so that they stop following every divot in the road.... is it typical of gassers to have the shackles in the front, if so, why? - the reasoning behind the moving the shackles back is stops the shortening of the spring when one tire hits an obstruction (think S shaped spring, but only on one side).

[1946Austin]

Nice stance! Hope it stays up in front once the engine weight is sitting on it!

[racingsnake440]

Front axle on and back on its wheels - well it would be if the rear wasn't on jackstands because the ET Streets lose air... Steering next

[racingsnake440]

That really cleaned the frame up! And it will make mounting the straight axle a lot easier now! Nice work!

Thanks, still got to blend the bottom of the frame into the box section and plate over the joins but happy with how it's looking.

John, this is the first time I've put new frame rails on a car - well second if you count the ones I cut back off...

[milner351]

You're making quick work of this! Sure can tell you've done this before! Nice clean set up with the front of the car on.

[1946Austin]

That really cleaned the frame up! And it will make mounting the straight axle a lot easier now! Nice work!

[racingsnake440]

I wasn't happy with the way the stock frame was going to work out with the straight axle so I decided to lop the front 2' off and replace with box section. I originally planned to run the rails down at an angle to go under the front of the fenders but I didn't like the way it looked and cut it all back off again - would have been a lot quicker if I'd made my mind up before finish welding it all...

Started again and cut the rails slightly shorter to fit behind the fenders. I'll have to put a small extension on to fit the shackle mount to and I'm also going to put the axle under the springs to make up the difference in height.

With the front crossmember gone I had to make something up to mount the radiator yoke to so a simple piece of box with some angle welded to it took care of that.

Next up suspension and steering!

[racingsnake440]

Aaargh, what have I done!!??

[racingsnake440]

Nice fab work! You must be going a little lower in front with the axle above the springs?

Thanks!

Not decided for definite on whether the axle will be above or below the springs but I want it to sit about the same height as my last one (pic on first page of thread). That had an early Econoline axle with a bit of a drop in it so I thought mounting the straight axle above the springs might come out about the same. Nothing's welded on the axle yet so I can still change my mind once I get it a bit closer to rolling.

And yes, I think I will be cross steering it.

[1946Austin]

Nice fab work! You must be going a little lower in front with the axle above the springs?