i know a guy that has some blocks of phenolic...enough to make risers out of but i was curious....is there a certain type that is ideal for risers?

Yes, Linen Phenolic is what I use.  Item LB-1.75-S from Plastics International

There's lots of different kinds, but the more layers of fiberous material bound in the resin, the better IMHO.

kirkll uses a really hard and heavy material for I beam risers, pretty sure he calls it G-10..**update.. I looked up G 10 and it seems to more like fiberglass than phenolic?? so I think it would be stiffer than phenolic??