For a cub and cleanup or mild port work is around 900. So which leaves you only 2100 left to play with. I would go override tranny, cool head, lockup clutch to start with. You will be suprised how fast that 3k will go when building a drag motor. Don't forget the insurance pancake bearing for your clutch you don't want to spend all that money and then have to split the cases again to fix the clutch rod welded to the ball.