Does anyone know of a good power steering gearbox to purchase. Summit has an AGR factory replacement gearbox, but I do not know anything about these gearboxes. I was trying to rebuild mine and found a lot of bad parts and thought it may be better to buy a new one. Thanks for your time.

68 Chevelle SS (Matching Numbers)

Or send your old one here for a quality rebuild.
http://www.steeringgearrebuilders.com/ Tell them you heard about them on Team Chevelle, Sam may give you a break on the costs.

A 94-96 Impala SS box should bolt right into your car and it will give the quick ratio steering. You will need to buy the adapters to convert the oring style lines to inverted flare so you can run your stock hoses. You can get those at napa through there Weatherhead line. You will also need the rag joint coupler to mate the steering shaft and the gear box together.