Many know me As Z from the slot car message boards i must say i love Z28'S!
Here is a MOD i have done to a scalextric Z28 that i thought i would share with you.
ENJOY!

Parts Used FLY C-3 Super tires & Stock FLY classic wheels.

First i took the Z28 apart i had to do two tiny mods to get this set up to work and get those steam roller tires stuffed under the Z's rear!
 it was easy anyone can do it!

In the above Photo you can see by the # 1 this is the bushing on the side of the rear without the gear. What i needed to do is sand the side of the bushing facing outwards towards the wheel making it much thinner like shown in the photo Above.
Next you will need to sand the nipple where the axle mounts in the wheel shown By #2 you will need to sand just a little bit off from here i used a moto tool to do it. 
All these mods are very simple anybody can do it!

Here is the whole rear how it will look when completed!