They mainly due sbc/bbc stuff and more than likely didn't have a 6 cylinder cam to try after they installed the cam bearings.
THEN I forget to check them prior to assembly and put the crank and pistons in first so getting to the cam bearings was even more difficult.
Lesson learned...insure cam goes in and spins freely prior to any assembly.
They usually ask you to provide a camshaft if they don't have one, at least a used one.
Also, put the cam in before the rods and pistons, you can bang up the lobes trying to snake the cam in around them. Then after you install the #1 rod and piston, degree the cam before you install the rest of the R&P.
