Shaft length is critical and must be specified exactly. Please see the ACPT order form instructions. U-Joint sizes are based on Spicer or equivelant sizes. Conversion joints are available for import cars and trucks. Carbon fiber shafts are available for most cars, vans, light trucks, heavy-duty trucks, and industrial applications. Custom built shafts are also available. Please call your local driveline shop or ACPT, or fill out our online information request form for details.