Actually, it will decrease the anti-dive... to increase it you need to raise the rear block (which also reduces the castor angle).

A bit of front kick-up is a good thing on bumpy tracks, as it allows it to absorb the bumps better. From memory, 0.8mm under either block changes the castor angle by 1°,

I have actually used shims under the rear block before, and that seemed to work well when I was using a spool, and racing on a tight track. A little less castor increases initial steering, and the arm angle allows the car to lean on the front more.

HiH
Ed