[ElGracho]

I figured KIILew would have been in on this one by now, but GQ1 doesn't mean non posi or any specific axle ratio. It means "Standard Axle Ratio" which you can look up in a table for your GVW, your engine, your trans, and your body style (Long bed, short bed, blazer, etc.)

For this case, from my 84 Light Duty Chevy Trucks Preliminary Data Book, from the power teams chart on page 78: A 1984 C-10 with a 4900-5600 # GVW, the LE3 4.1l 6 cyl and the MM4 4-sp would have 2.73 gears as its GQ1 option. With the MM7 4-sp, it would have 3.08's. With a 6100# GVW and the MM4 it would have 3.08, and MM7 it would have 3.42.

In this case, MM7 is the 4 speed with overdrive and the MM4 is the 4 speed without.

Mind you all of these are C10's even with 4 different GVW's. The C20, K10, K20 etc. are all in different tables.

On the other hand, the optional axle ratios are fairly easy to decode. GU2 = 2.73, GU4 = 3.08, GU6 = 3.42, GT4 = 3.73, GT5 = 4.10, HC4 = 4.56. As long as you don't have the 'standard' ratio for your particular combo, you can pretty easily figure out what your truck had originally. If you do have the standard ratio, you need a little more information and a table corresponding to your year to figure it out.