Nice job with the 3-D printer. If it's waterproof you have a winner!
We've had a couple of instances in our club of sputtering cars due to water infiltrating the coil box. While the plastic replacement kits available from the vendors may not be quite as polished as the ones sold years ago by Fun Products, they do the job. Re-use your contacts if you can. If you need to replace them, the two main vendors sell contacts of different quality so you should check them out before ordering. You want the ones that look like this. They're closest to the originals.
If your contacts have lost their "spring" you might try what I and a couple of other fellows have done.....Double them up! Blasphemy I know, but it works....problem solved.
A friend replaces coil box wood with a material designed for outdoor signs. Me, I'd just get the plastic box kit. When putting it together, be sure all wires and connections are well insulated from the metal box. We've had two instances recently of bottom wires shorting that way. It's also a good idea to solder the contacts to the bolts that run thru the insulators. Speaking of which, we recently had trouble on a tour with one of our cars because the nuts holding two of the insulators were loose. Tightened up and the car ran fine.
The attached photo shows carbon traces on the wood of a coil box from a '22. Got wet and never worked properly again.
