How They Should Have Made It – Recent Scalextric TransAm Cars – Part 4, AMC Javelin, the Build

by Bob Ward


So… How should they have made it?  We’ll tell you up front.  Scalextric should have made the Javelin a sidewinder even if only to keep it consistent with all the other 1/32 scale classic TransAm cars on the market.  That by itself is more than reason enough but there’s more to it – quite a bit more.  To cut all that as short as possible so we can get on with building the car, it has to do with where the magnets need to be placed.

If you want ultimate grip for a totally stuck-down car the magnet goes right under or just forward of the rear axle.  You can have that with any of the common chassis layouts: inline, anglewinder, or sidewinder.  But, contrary to the stereotype that has prevailed for decades on the Internet, most magnet racers don’t want a car so stuck down you barely have to drive it.  They actually want what most non-magnet racers say they want, a car that drives “realistically”, however they may define that.  They just want it with higher limits.

For these magnet racers the essential magnet position lies jut forward of a sidewinder motor.  And, in our experience, it can’t be just any magnet configuration.  It needs to be a bar magnet that delivers a healthy amount of downforce over as much of the car’s width as possible in order to make the car drivable and capable of cornering tail-out to a significant degree without abruptly losing downforce and snap-spinning, as occurs when the back end of the car slides out enough for a cylindrical or small rectangular magnet no longer to be over the track’s steel contact strips.  You can’t get a bar magnet of the size, shape, and strength you need in the right place on an inline or an anglewinder because the motor sits right where the magnet needs to be.

Why, then, do we have inline and anglewinder cars?  Some cars, of course, simply are not wide enough for a sidewinder setup to fit.  For other cars it’s mostly to provide the weight distribution needed for non-magnet cars to drift through the corners.  You can either have the weight distribution you need for non-magnet racing or the magnet positions you need to provide desirable options for magnet racers.  You can’t have both on the same chassis, at least not without interchangeable motor pods. And that means, contrary to another popular myth, that, except in the limited sense of putting higher-end, more precision (and expensive) parts on the car, what makes the best non-magnet car does not make the best magnet car.

And if it’s true that the overwhelming majority of the world slot car market, actual and potential, is magnet racers, you know which side of the question Scalextric, which makes one-piece-chassis slot cars for the masses, needs to come down on with every car they produce that’s wide enough for a sidewinder installation. Hence, a sidewinder Javelin.  (If you want more information on all this, see our 3-part article series “Musings About Magnets”)  Now, on to the car build…

We had been casting about for a sidewinder chassis the Javelin body would fit without major alteration.  Our first candidate for this kind of thing is one of the CRSes (complete running chassis), Mustang/Camaro or Dodge Charger, from Pioneer.  Alas, one was too short and the other was too long.  Of course, it’s no big deal to lengthen or shorten a chassis but we wanted to keep this as simple as possible.  Then we discovered a semi-junk Scalextric Dodge Challenger we picked up somewhere along the way and found that the wheelbase was a perfect fit.  We also found that if we put the Javelin’s wheels and tires on the Challenger’s axles the tires filled the fenders perfectly with just enough clearance.

The Challenger chassis did need a few modifications to fit the Javelin body and delver the level of performance needed to make it competitive with our other Scalextric and Pioneer classic TransAm cars.  The photo below shows what we did (not necessarily in order).


  1.  Front and rear valences cut off at body mounts.
  2. Sloting Plus 101003 universal plastic track guide installed and cut to desired length.
  3. Javelin wheels and tires installed on Scalextric axles.
  4. Stock magnet moved to forward magnet position and booster magnet added.
  5. Chassis sides narrowed to fit Javelin body.
  6. Styrene strips added to body sides to stiffen chassis and fill body-chassis gap.
  7. Javelin exhausts shortened and glued to chassis sides.
  8. Piece of sheet styrene cut to rear contour of Javelin body and glued in place.
  9. Rear body mount cut from junk chassis and glued into place.

The car uses the Javelin rear body post in its original location and the front body mounting points of the Challenger chassis with the Javelin front body posts relocated accordingly.  The booster magnet is held in place entirely by magnetism and bumps up the magnetic downforce, as measured on our Magnet Marshal, to just the level needed to meet the specs we have established for our classic T/A cars.  We also glued the DPR trapdoor in place, as we don’t ever intend to convert the car to digital, and we replaced the entire DPR wiring assembly with simple silicone-insulated lead wire.  We did all the gluing on this project with Plasti-Zap except for the rear body mount and the front body posts, which we did with Gorilla Glue.


This image shows the relocated front body posts.   Since we had to relocate them we couldn’t use the lugs built into the front grille/bumper/valence/spoiler piece so we cut the lugs off and glued it to the body, adding a few pieces of styrene for extra strength.


We found the Javelin’s original tray interior to be a step in the right direction for weight saving and for accommodating different motor installation, but for this conversion we decided to adapt a Pioneer full-depth interior for two main reasons.

  1. We know many hobbyists like full-depth interiors and we wanted to show how it can be done.
  2. The fit of the Scalex interior’s roll cage was terrible, while the Pioneer cage looked like it was made for the Javelin body.  In addition, it was a very easy installation, much easier than fabricating a new roll cage.


Here you can see what we did to adapt the Pioneer interior for the Javelin conversion.  First, we took the sides off to save weight.  Even back then most race cars had stripped interiors, so the absence of the tub sides will not really be an issue for most people.  The interior had to sit quite far forward on the chassis to position it properly, so we had to cut a notch in each of the tub’s lower front corners, indicated by the arrows, to clear the front tires.

The interior isn’t attached to the body.  Instead, we glued a piece of a body post from a junk body (the round blue shape in the right-hand photo) into the transmission tunnel, positioned just above the hole in the chassis for the case screw.  We could then attach the interior tub to the chassis with a body screw.    The rectangular white piece is a length of styrene strip placed to sit on top of the motor and hold the rear part of the interior clear of the lead wires.


Here’s a nose-to-nose comparison  of our modified Javelin (left) and a stock one.  The patterned rectangle in between our car’s rear wheels is a piece of carbon fiber sheet to reinforce a repaired area where an epoxied-in magnet had been removed from the rear magnet position, tearing out part of the chassis with it.  It really was a semi-junk chassis when we started with it.  Now, our “Javellenger” is fully legal for classic TransAm racing and ready to take on the competition.

We should mention that we’re aware that it’s not likely that lot of people will do this particular kitbash.  For one thing, most of our readers probably don’t have a Challenger  they want to use as a donor car.  For another, we have no doubt that the 3D-printed chassis people are producing a sidewinder chassis for the Javelin or soon will be, and that will be an easier project for most people.  Our main purpose here is to build a car that comes as close as possible to showing “How They Should Have Made It”.  And maybe, just maybe, we’ve given you a bit of a glimpse into how somebody else is going to make it.

Have questions or comments on this article?  Post them below or e-mail them to



One thought on “How They Should Have Made It – Recent Scalextric TransAm Cars – Part 4, AMC Javelin, the Build

  1. The whole time I was reading, I was wondering if there was a 3D chassis available. I was also wondering what glue you were using. Of course you answered this, but I’ve never heard of “Plasti-Zap” until now.

    Great article. Looking forward to the next one.


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