The complete seat slide is not currently available for Bugeyes and early Spridgets. So if your car is missing the tracks, you have to get creative. Here's a solution.
This seat track set allows you to mount the seat base to tracks to make your seat adjustable. You can drill and fit these to the underside of your seat and you'll have an adjustable seat that's easy to operate with excellent ball bearing action.
It's an intermediate level project to get these to fit your car, so some assembly required. You'll need to modify the studs to fit your particular seat frame. It's not hard to drill new holes in track and put in bolts that fit your car and your seat spacers.
We've loaded a few photos of a seat frame fit with these slides. This unit is ready for installation in a Sprite. You'll notice we adapted the bolt pattern to fit the wood spacer blocks and floor pans. (We painted the tops of the slides black, but they can be left unpainted.)
Sold as a pair. If you want to do both seats in your car, get two sets - one for each side.