Reusing LS main cap bolts is a very important question to consider when rebuilding an engine. The answer, however, isn't always cut and dry. Generally speaking, it's not recommended that you reuse main cap bolts as they are usually designed for single use only. This means that if the bolt has been used once before, its strength and integrity may be compromised due to stretching or weakening during the initial installation process. Additionally, many aftermarket performance companies will recommend replacing them with every build in order to ensure optimal torque readings and clamping force on your crankshaft bearings. As such, it is generally best practice to replace all of your LS main cap bolts whenever you're doing a rebuild or overhaul so as to avoid any potential issues down the line.