I purchased a replacement chassis for $ 24 and modified it to fit the Commodore.
Chassis has to have some trimmed off the front as well as the rear. This is shown in the pictures below. The rear mount posts have to be shortened to get the right body height. The front mounts are too short so I used the styrene in layers until the body was resting on the styrene. thread . with the body in the correct position I drilled through the body mount posts into the Styrene. I used a 1mm drill into the styrene . I used a body screw with a sharp point cut the thread in the styrene. Once the body was the correct height & position on the Chassis
A Ninco deep wood guide can be fitted but the post hole should be bushed as it is too big for the Ninco guide. A bit of the rear top of the blade needs to be removed to clear the chassis. I used Brass tubing as a bush for the guide post and glued it in. A Scalextric deep guide could also be used but check it does not lift the front wheels off the track. Also add awasher over the post to make sure the gide does not drop to far and passes the guide stops.