How do you do a straight front axle conversion on a 99 Tahoe?

well there are many ways first you need to deside wether or not you want to keep your original t-case if you use a Ford axle you can keep your t-case if you use a Chevy axle you will need to change your t-case to a passenger side drop t-case because the Chevy axle has a passenger side pumpkin now if you have decided what axle you are gonna use u need to decide if you want to make your own spring hangers (leaf or coil) or use ones off of another vehicle or buy a expensive kit then after all thet is figured out you will need to change your pitman arm get a draglink and possibly a high steer kit then after all that you will need to get your computer tuned to delete abs(brakes) and front axle (internal electric locking hubs) it is fairly easy to do and will give you 3-9 inches of lift depending on where you put your spring hangers and whether you put the front shackle up or down also you will need your driveline modified and put Chevy brakes on your ford axle you will also need to make shock mounts and modify your brake lines if you want to use a Chevy axle you will need to change your t-case to a 208,203,or 205 this will require a th350 style for your 4l60e with a clocking/adapter ring then you will have to modify your t-case for a vss(vehicle speed sensor)