Proheader TCA-5557UL - Chevy Bel Air Fullsize Tubular Upper & Lower Control Arms Set These are the Authentic original UPPER and LOR tubular control arms!! Ready to install and GO! Works with stock coils or coil over springs. Control arms have ball joints pre-installed so there is no need to run to the machine shop. These kits are matched for yspecific vehicle, saving you time and money! Sold as a set. Will bolt to ystock spindles. HUGE TUBE DESIGN FOR LESS DEFLECTION. ; Lors are 1.625 OD - .156 wall DOM tubing Uppers are 1.125 OD - .125 wall tubing Special cam plugs allow for more caster adjustment, giving vehicle more high speed stability. The upper arms have 4 degrees of positive caster. The lors are stock.