About 20 years ago, I bought a complete 489 housing center section with 3.55 gears and Sure Grip from Randy's Ring and Pinion. It was all new parts including the housing. It has performed flawlessly. They are still in business at this website: www.randysworldwide.com
I have Randy Ring & Pinion 489 center section in my car for about 20 years. And last 15 years stroker engine and now 6 spd manual trans. I change gear oil regularly to help it last.