Torsion Bars, Springs, Motor Mounts and Sway Bar ->Conversion 318 to 440

Hello.
Finally I´m finishes with my engine (it´s a 440 from a 1969 Road Runner). But before I put it in the car, I would like to know if it makes sense to change some parts due to the power and weight of the 440 engine.
The car is a 1973 Dodge Charger wich came out of the factory with a 318.

Wich Torsion bars would you recommend? Especially wich diameter? I want to use the car as a fast daily driver... No drag strip...

Wich Motor Mounts do cause the least problems? Especially in relation of the hight of the engine and a proper position.

Is it necessary to change the Springs on the rear axle?

Do you think a Sway Bar would make sense? Wich diameter would you recommend?

If you know a certain manufacturer for the parts above, with wich you had good experience please let me know. Also an address where to order would be great, because its not so easy to find a trustworthy shop only by using the internet.

Thanks
Axel

Contact Firm Feel in Washington. For sure Dick can hook you up. Hotchkis I'm not sure due to the year of your car.

Mancini Racing has a lot of suspension stuff but they don't show motor mounts to adapt a 73, only a 72. They do have a lot of suspension stuff, however, and have been very helpful whenever I dealt with them.

Sorry if I'm mentioning things you already know. I would suggest a set of stock diameter big block torsion bars which you can add later. The car will sag a little bit in front with the 318 torsion bars & the heavier engine, but you can adjust the ride height up by turning the big torsion bar bolts. You can search for "conversion motor mounts" online. You should double-check the oil pan you have vs. clearance with a small block K-member. Now the obvious... the transmission is different & your rear axle better be a 8-3/4" (no bolts on the back - option for 318 cars in '73 Chargers) or it won't take the strain of the extra horsepower. Rear spring should be OK, but you could always put in some stock biased (more leaves on passenger side) leaf springs at a later date. The rear sway bar is optional for slightly better handling.

Thanks for your help. That I have to change the transmission is clear. I swapping to a 833 Manual Shifter. It´s only a 23-Spine, but I hope it holds at least some months.... About the rear axle I´m not to sure wich one is exactly in the car. Problem is, that I was spending the last weeks building the engine, and the car itself is in a barn about 60 miles away. So it´s not so easy for me right now to go there and measure every detail immediately. I have some pictures from the rear of the axle and the place where the motor should be placed (I don´t know how this is called in english... we call it "Motorraum", like Space for the Engine)

You have an 8 1/4 rear axel with the iso rubber mounting for the leaf springs. The 8 1/4 is reasonably stout, Mine has lived in My 74 for over a year with aprox 550hp on street tires with a 727, have a 8 3/4 to going in soon. I made my own motor mounts for my big block swap, but I understand you can purchase them from a "Schumacher"?. There are some threads on this forum about BB swaps.

I would swap the steering box before you put the engine in at least.

Well your in the protouring section so I would recommend calling Firm feel. I would suggest a firm feel stage 3 setup, well worth the money.


http://www.firmfeel.com/b_body_mopar_parts.html

I'm still small block but have a heavy 73 wagon. Looks like you don't have a front sway bar. There were 2 available for your year from the factory. The larger is the 15/16ths. Firm Feel makes a 1 1/8" and 1/4" that is a bolt in. They also make a 7/8" rear bar but you will have to delete the iso mount system to use it.

You will DEFINITELY want to upgrade the torsion bars. I went with the FF 1.06 and absolutely love them. If you have rusty T-bar adjusters PST is the only place I have found that has them for post 72 cars. They are fine thread too.

For sure get the FF steering box. A million times easier to swap with the motor out.

You car also uses the spool type motor mounts. They tend to be a lot less problematic compared to the biscuit mounts. You can fill the gaps with silicone and IIRC there are urethane inserts you can press in.

You also have the iso mount rear springs/axle housing. The springs in the rear of the car are going to ride like a sponge. I picked up 2 right side MP XHD springs but cannot comment on ride height or feel yet as they showed up yesterday. I've already done the iso delete so they will be a bolt in for my car, but not yours as it sits without welding a washer onto the spring perch of your existing housing to use the smaller locating pin.

Rear shocks you can get anything. Front shocks, another 73 nightmare. The Bilsteins by Race car Dynamics were the only bolt in when I bought them early this year that were not ultra plush junkers that won't control increased spring rates . Someone on here modded their lower control arms to use KYB Gas-a-just from a Monte Carlo I believe. However I think there is now a adjustable front set, made by Viking? I'll let you know if I grab a set and how they work.

Lastly, 8 3/4 rear axles are not too hard to find that bolt in. You can use later c body if you keep the iso setup. Earlier if you make the change. However it's a wider housing so wheel width, tire size, and offset well be a factor if you don't want rubbing. I'm running a 70 C body 8 3/4, non iso, with 9.5" wide rear wheels, 5.5" back spacing, and 285/40/17 tires with no rubbing issues. I have a wagon though, not sure if the wheels arches are physically farther out from centerline. Also, you can use narrower rear ends for other cars that are more plentiful as having new perches put on is ~$150 but again wheel offset will be important so you are not rubbing on the leafs.

Hello. Thanks for all your replys.
There a still a few things I don´t understand?
Why do I have have to change the steering box? Does the engine not fit with the one I have already? I I need to get a new one, is there a recommendation?

If my car came out of factory with a SB 318 and doesn´t have mounting holes for a sway bar - how can I mount it? Are there special kits or do I need to build something by myself? And if yes, where exactly do I place the sway bars for best performance?

What does the term "iso mount" mean? Maybe its obvious, but I didn´t hear that before.

Thanks

Your picture shows a front sway bar, but the rear requires a relatively hard to find mounting plate on each side. Making your own that will work is probably your best bet. The 71-72 is slightly different from the 73-74 If you do look for these. The Iso mounts are the "isolation" bushings, the rubber inserts around the axles springs. Earlier cars did not have these, hence the difference in sway bar mounting plates.

Also I have a set of Schumacher conversion mounts, new if you are looking. Not sure what shipping to Germany would be. I just used a set in a similar swap and had no issues with fitment.

Info for your rear sway bar questions and expanding on the comment about the elimination of the rubber isolation assembly

Here are a pair of 73-74 rear sway bar assemblies I have. One I've modified to eliminate the ISO mounts on the rear axle and use the older style shock plates. I tack welded washers in the large locating hole in the axles spring mounts as well.

Stagepirat said:

Hello. Thanks for all your replys.
There a still a few things I don´t understand?
Why do I have have to change the steering box? Does the engine not fit with the one I have already? I I need to get a new one, is there a recommendation?

If my car came out of factory with a SB 318 and doesn´t have mounting holes for a sway bar - how can I mount it? Are there special kits or do I need to build something by myself? And if yes, where exactly do I place the sway bars for best performance?

What does the term "iso mount" mean? Maybe its obvious, but I didn´t hear that before.

Thanks

Click to expand...

You don't have to change the steering box. However if you plan to upgrade it's much easier while the motor is out.

For 1973 the B body went through a bunch of revisions. The 2 biggies were isolating the front K member, sits on big rubber bushings, and isolating the rear axle from the leaf springs.