Terry Ives, in California, has a vintage square tubing framed kart that he just loves. He's been taking it to all the vintage events for 10+ years. I have a picture of him driving it at Riverside in 2008 and 2019. In the same corner.Hey Al, its been a while. I have not written about the tubing material. It does make a difference. I had a chassis builder make me a chassis out of an oval shaped tubing once. No wonder the rules specify round tubing only. Not sure if this holds true today but all the "Factory" drivers were not on what the public was riding.