Coil-over conversion

[walts333]

Have a 73 Dodge Charge.  I'm considering a front end coil-over conversion.  Thoughts?  Pros or Cons

[DynoDave]

Welcome aboard Walts333.

A timely question, as I was just wondering about this myself. Art Morrison has an ad in Mopar Collectors Guide for their new drop-in K-member and front suspension. My big gripe about suspension changes is that sometimes they put chassis loads where they were never intended to go. This Morrison piece bolts up right to the frame.

They seem to all offer a great deal of adjustability....being able to get a lot more caster than the factory setup for instance. This can be very valuable, along with having better bump steer, adjustable coil overs for precise height adjustment, a host of coil spring rates, double adjustable shocks, etc. etc. Adjust adjust adjust.

If all of that flexibility in adjustment is something that is important to you, and that you need to meet your performance goals, these setups (and their expense) can make a lot of sense. For just cruising around town and some occasional spirited driving, I'm not sure it's money well spent.

My other concern is future servicability. On a long road tour, like the Power Tour, Drag Week or Cruisin' the Coast? Have a bushing fail, a bad joint, etc? Where are you getting parts? Lets say you buy the Morrison setup as an example. If Morrison goes out of business next year, then where are you? Not a major concern to some, but having spent my life in the auto / repair industry, I can't help but think about it.

[jeremy]

Coilover setups have been discussed extensively and vehemently on forbbodiesonly.com. It's definitely not a clear cut win for coilovers, although it's a big lose in the $ department. My take away is that there are only two advantages to coilovers - some say they are more "precise," and it gets you into rack-and-pinion steering intead of ball-and-trunion. One of the downsides is that you are moving weight from a point under the floor of the car, where the torsion bars live, up into the fenderwell. How noticeable that is, I don't know. But you can do a lot of weight shifting in the car that adds up. Move the battery to the trunk, replace cast iron heads and intake with aluminum, replace iron manifolds with steel tube headers, fiberglass hood, tubular suspension, Borgeson steering box - I think it would all add up to a noticeable difference.

I went with the best version of the stock suspension - although maybe that is debatable too! Bergman has stiffer torsion bars than the 1.03 bars I got from PST. I've seen people complain about the stiffness of the PST bars though (PST's answer is to use Bilstein shocks instead of el cheapo brand). Also, you can only be so stiff on a bumpy public road before you lose performance. The suspension has to conform to the road a bit.

You should be able to get to the magic 3 degree caster setup with the factory upper control arms and adjustable strut rods. There's a trick using offset bushings that should give 2 degrees caster in the upper control arm, and the adjustable strut rod should give the last degree. That's what I'm trying, but my car is still on jack stands.

Several vendors have tubular upper control arms with the correct caster built into them, but they've got squeeky polyurethane bushings. I doubt polyurethane in the upper control arm is worth it for a street car.

I'd have to try the rack-and-pinion steering conversion before I'd commit money to it. It has to be significantly better than the Borgeson steering box with PST's C-body end links and tie rod ends.

Another thing to consider is that your savings can go into better tires, and that will make a difference.

[jeremy]

One thing I would consider is converting the rear end to a Challenger independent rear suspension. Uncle Tony's Garage did a video on it. That would give you factory reliability along with better handling. I doubt more than one person has done it and maybe no one else ever does it, but it seems like the way to go to me.

[walts333]

Interesting you mention the weight shift. Others have mentioned it but in the detail you did. I am replacing the 318 with a 440. Hence I need to replace the K frame, and I thought as long as I was doing that upgrade to a coil over. Some have told me they have instruction on how to weld up a big block K Frame onto the small block, but I dont want to go that route. I will be replacing the intake and heads with Summit Aluminum units and headers so that should help move the weight back some. Relocating the battery, although not a ton of mass, will help too. Thanks for the input

[Nacho-RT74]

You don’t NEED to replace the K frame. Even maybe replace the K member could be the “best” and correct option, engine mount “adaptors” are available… althought dunno if Schumacher services are already back on bussines with the new owner. They were in a production pause while the changeover.

www.engine-swaps.com/

Honestly, my 74 has been a driver (REAL DAILY DRIVER ) on a heavy transit city ( Caracas ) and bad condition roads country ( Venezuela ) for LONG time untill dissasembled for a deep resto process and never have felt the need to swap stock assembly to coil overs.

Just get a thicker T bars and sway bar to hold the extra weight of the 440 and call it done.

[jeremy]

Hey, look what Nick's Garage just dropped - 



How much power are you looking for?  If you can make it with the 318, why have a 440 adding weight and taking up space?  Why buy all the extra accessories and brackets and stuff the 440 will need, when you can use what you've got?

[jeremy]

Now that I've watched the video, that is crazy power (406 hp 442 tq) for a 318 with iron heads and manifolds! I'm looking forward to seeing what it will do with the spacer. Would love to see what it would do with headers and good aluminum heads. I didn't catch whether any work had been done on the factory heads or not. I'm guessing there are still gains to be made.

walts333 - With your 73 one of the big handling problems you are going to have is with your "luxury ride" rear suspension, which added a bunch of extra rubber around the leaf spring to try to soften the ride. You might want to consider Firm Feel's ISO Delete kit. I say "might" because I've been waiting half a year for Firm Feel to send me a rear sway bar, and you might be able to piece the kit together yourself for less money.