May be easy, but it sure ain't gonna be cheap.
It could be as easy as needing just syncro's. The gears sell for about $500.00 each. But you may need the countershaft to fix fifth on that tranny. And that sells for about $1.050.00.
There is a guy Ricks Stick Shift on 49th st. that is really good with those transmissions. 585-9885.