I randomly happened to catch a shiny Kadabra in Cerulean Cave in my Leaf Green version. It was caught at level 58. Can I get all of the EV's that Kadabra can get? I'm no expert when it comes to EV's.
Yes it can. EVs can be obtained at any level, and a Pokemon has the maximum of 510 (or 508 useful EVs).These 510 EVs can be fully obtained even when training at level 100 (in Gen IV or V, I think the older generations didn't let that happen).