That does not sound right, unless you are talking about the installation kit and a posi unit, plus the part I was thinking of which makes up the difference in the pinion shaft diameter between the chevy and he BOP pinion bearings.

As far as I know, it's not that big a deal.

What were they trying to sell you for that kind of money?

Also, since you're already in series 3 gears, I would expect you only need Richmond gears in the low 4's and an installation kit. the whole thing should cost you less than $400. (Or so I would think.)