Saginaw 605 gear has become popular for tight-space conversions. This gear is lighter duty than the 700- and 800-series designs. If you select a 605 for your conversion, do not bother with a recycled unit. There is no such thing as a "good used" Saginaw 605. A better bet is a quality rebuild from a reputable source or an 800/808 or 700/708 gear.