Episode 5 66 Chevy Burnout G10 VAN 

Those plastic trays do more than guide the pushrods. They are also the same shape as the top of the lifter to allow you to rotate the cam, push the lifters into the trays with the trunions off, and do a cam change without removing the heads. A cheap replacement as well. I also would change the valve stem seals while you had the springs off, if you didn't do that at the time.. Although you can gently feed a dowel through the galleys alongside the camshaft to hold them up while in the engine as well.