I Need Engine Experts! 340 Roller Lifter and Pushrod Issue
Run the oil pump with a drill while rolling the motor over with a ratchet/socket. The lifters will oil up if you roll it around several rotations, which is pretty easy with the plugs out. Then check your push rod length as soon as they pump up. You really only need 2 that are linked together to pump, so you can hold a little pressure against only those 2 while another person turns the motor.
Mike @ B3 will be a tremendous help to you in getting the frigonometry figured out....lol.