I did an E6-350 and I used dowel rod with rare earth magnets epoxied to the end. layed card board on top with 12 holes for dowels . pulled up lifters and clamped close pins on dowels. worked great.

Buy the biggest extended magnets you can find and hold them up with rubber bands or turn your truck upside down that works too , also can ask to barrow cam lifter sticks from your local mack dealership.