You can reuse your factory retainers, locks, seats, and seals, as well as your factory pushrods! Pushrod length should always be measured though. You may need to change to a different length pushrod if you change to a different style of lifters. This will be common for DOD applications.
Some lifters do vary in overall length or take different amounts of preload. The item "Texas Speed TSP Stage 4 Low Lift Truck Camshaft for Chevrolet 4.8L 5.3L 6.0L LS" is in sale since Thursday, July 30, 2020. This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts\Engines & Components\Camshafts, Lifters & Parts". The seller is "amsracing" and is located in Bossier City, Louisiana. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Indonesia, Taiwan, South africa, Thailand, Belgium, France, Hong Kong, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Philippines, Singapore, Switzerland, Norway, Saudi arabia, Ukraine, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Malaysia, Brazil, Chile, Colombia, Costa rica, Panama, Trinidad and tobago, Guatemala, Honduras, Jamaica, Antigua and barbuda, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Saint lucia, Montserrat, Turks and caicos islands, Barbados, Bangladesh, Bermuda, Brunei darussalam, Bolivia, Ecuador, Egypt, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman islands, Liechtenstein, Sri lanka, Luxembourg, Monaco, Macao, Martinique, Maldives, Nicaragua, Oman, Peru, Pakistan, Paraguay, Reunion, Viet nam, Uruguay.