I am planning on cutting spring pockets for clearence in the front
For my 1995 caprice. I want to use cutting wheel,any suggestion
On what grade wheel to use?I heard the rite one will cutt like butter

the cut off wheel you are looking for is made by hobart and costs around $700, and is commonly referred to as a plasma cutter. j/k.
on a serious note. i have had alot of good fortune with dewalt 4.5 inch grinding wheels on an angle grinder. the thinner, the better, but you also have to control it more, as they like to snap easier.

ps, wear safety goggles.