I am in need to replace the 605 power steering box on my 59 Impala. I have heard that there is a 605 box that has a little quicker steering ratio than all the others, but I can't confirm that or which one it is. These steering boxes came on late 70's/80's intermediate cars.
Late Model 12.7:1 quick-ratio gearboxID markings YA, WS and HX Line Thread Size: M18x1.5 and M16x1.5 Number of Mounting Holes: 3, (missing leg H-pattern) Input Shaft Diameter: ¾-inch Output Shaft Diameter: 1 ¼-inch Number of Turns Lock to Lock: 2 ½ - 3 1984-'88 Monte Carlo/Malibu with Z65 suspension 1983-'88 Malibu, El Camino 1982-'92 Camaro except FE1 soft ride suspension 1984-'87 Regal with FE2 or FE3 sport suspension 1983-'84 Hurst/Olds 1985-'87 Cutlass with 5.0 (VIN code 9) 1982-'85 Trans Am 1986-'92 Firebird except FE1 suspension 1986-'87 Grand Prix with FE2 touring or F41 heavy duty suspension Pre-'76 12.7:1 quick-ratio gearbox Line Thread Size: 11/16 x 18 and 5/8 x 18 Number of Mounting Holes: 4, (H-pattern) Input Shaft Diameter: 13/16-inch Output Shaft Diameter: 1 ¼-inch Number of Turns Lock to Lock: 2 ½ - 3 1967-'76 Camaro, Firebird 1970-'76 Monte Carlo/Malibu 1964-'76 Chevelle 1977-'79 12.7:1 quick-ratio gearbox Line Thread Size: 11/16 x 18 and 5/8 x 18 Number of Mounting Holes: 3, (missing leg H-pattern) Input Shaft Diameter: ¾-inch Output Shaft Diameter: 1 ¼-inch Number of Turns Lock to Lock: 2 ½- 3 1977-'79 Camaro, Firebird 1977-'79 Monte Carlo, Malibu 1977-'79 Chevelle Jeep/S-10 14.0:1 quick ratio gearbox Line Thread Size: M18x1.5 and M16x1.5 Number of Mounting Holes: 3, (missing leg H-pattern) Input Shaft Diameter: ¾-inch Output Shaft Diameter: 1 ¼-inch Number of Turns Lock to Lock: 3 - 3 ½ 1991-'92 Fleetwood 1992-'95 Grand Cherokee 1984-'93 Comanche 1984-'95 Cherokee/Wagoneer 1983-'86 Bonneville 1982-'93 2WD S-10 Blazer and pickup
The standard 605 is allread too quick for the alignment specs on the 59. It gets worse with radials and smaller steering wheels. You can't get enough caster to make it stop twitching on the road.