From slip to posi? Best bang for the buck?

[Hazieview]

Hey guys I am constantly debating what to do with my slip differential rearend.

I have a sb400 350th trani and a .308 slip differential rearend.

I dont really mind the .308 gears but I do not like the slip differential.

I want a posi!

I ask the guys at the fab shop how much it would cost to turn my rearend into a posi track and beef it up a bit. They said probably around $1800 and I about fell in the floor.

What do you guys recommend? I want the rearend to be pretty new and relialbe since my trani and motor are.

So should I turn mine into a posi?

Buy a posi and have it rebuilt?

I want it beefed up a little too because I'm going to be throwing better than 550lbs of torque at it.

Thanks guys!