Washer on Motor mount?

[Tmwoodall]

Is it advisable/doable to put a single washer between each of the three points where the motor mount attaches to the block? I ask for my headers, they clear the motor perch by about 1/4" or less. I'd like to get just a bit more space up in there without buying tubular perches if possible. If they weren't ceramic coated I'd just let the vibrations dent the tube into shape but am afraid that would cause rust at the dent and I would soon see it spread.