i think they are about 7" tall. they are also very wide. you will need to gear way down to use them. the e-revo has a pretty long wheelbase, but isn't all that wide, so i would use 1/2 offset wheels.
They say a good mechanic only needs 2 tools - WD40 & Duct tape. If it moves, and its not supposed to, duct tape. If it doesn't move, and its supposed to, WD40.