"Vai's main squeeze is the remainder of a green Charvel Strat. This ax was originally built for
Grover Jackson, who let Steve play it one day and hasn't seen it since. "Steve always has that ax within arm's reach; that guitar is Steve," says Elwood. The body is made up of basswood and is loaded with custom made DiMarzio pickups; two humbuckers and one single-coil in the middle position. Steve had the inside of the lower cutaway shaved away to just up to the edge of the pickguard to increase his reach on the neck (GW 1/87) "
Straight off this here site:
http://www.jemsite.com/axes/model/charvel2.htm