I've got the P/S box off my car and I'm not sure if it's original or not, but before I send it off for a rebuild I'd like to know if it's quick ratio or not. How many turns lock to lock should a slow one be? How about a quick ratio one? If I already have a quick one I'll get it rebuilt with a quick ratio.

spin the rag joint lock to lock, its probably the slower 4 1/4 turn unit. Faster ones are 3 1/4 or less. I have a few of the 3 1/4 turn ones if you ever want to upgrade.

I must have a quick one, it's 3 turns exactly lock to lock. Must've been replaced at some point. I can feel the difference between that one and the box in my Caprice (real slow).

You have to be carefull about just counting the total number of input shaft turns. Some gears, (particularly Camaro and Firebirds)have travel restrictors inside the gear that considerably restricts the travel of the gear. A gear that has restricted travel will also have less input shaft turns lock to lock and might give the impression of a faster ratio gear if you just count input shaft revolutions.

The only real way to determine the gear ratio is to carefully measure the total number of input shaft turns (down to the closest 1/10 turn). Then also measure the pitman shaft or pitman arm travel with a protractor. Then divide the input shaft turns by the pitman shaft turns and you will end up with a ratio.

BTW there are a few variable ratio gears (different ratio right on center versus a faster ratio near full lock)that really screws up the calculation.

The other way is to look for an ink stamped two letter code on the forward aluminum end cap or on the aluminum side cover. I have listed the two letter broadcast codes for nearly all of the 12.7:1 fast ratio gears as well as a lot of the Camaro, Chevelle, and Caprice gears at
www.corvettefaq.com/A-car.asp (http://www.corvettefaq.com/A-car.asp)

jiml82 is absolutly correct. it has to be measured very carefully. ther is not much difference between the ratios.