I'm new to quarter midgets and I've been told to start my 7 yr. old in a medium chassis. Does it matter if I start him in a 76" or a 78"?

There are a couple of things to consider here. The 76", 78", 80" size designations refer to overall length bumper to bumper. Each increase in "size" (overall length) brings with it a corresponding increase in wheelbase and roll cage height, and the crossbar in the front of the cockpit where the steering shaft bracket attaches gets higher as the size increases. From a performance standpoint, the lower cage height (lower center of gravity), lower overall weight and shorter wheelbase are desirable, so from a competitive standpoint most try to utilize the smallest chassis their driver can comfortable fit it. Most chassis have wide adjustments of pedals and steering shaft height.

If you are looking to buy a used chassis, the smaller cars can be quite affordable as obviously there is an active resale market created by the fact that kids naturally outgrow their cars (and helmets, and driver suits, etc!).

Hope this helps, racing quarter midgets with my kids was one of the best experiences ever for our family. Good luck!

I appreciate the advice, I bought a large chassis with the mindset of he'll grow into the car and run it for years. I have been advised by a few to start him in a medium chassis at his size. I am doing so.