Do you have a priming tool? If so how about adjustable rocker with the proper length pushrods? If yes to both prime the motor first while turning the motor over with no pusrods and then check the lifters If no to both questions put them in the motor, make sure they rotate freely in the lifter bores and go for it Do not let the motor idle at start up, make the motor run at or above 1500 RPM for 20 to 30 minutes to break the new cam and lifters in Also make sure the motor starts up immediately , no prolong grinding on the starter