Quick Ratio Steering Box?

[Big Block Bob]

My 1981 Malibu has stock round top steering box and I want to convert to quick ratio box. I have read to use 82 - 91 iroc box, but wouldn't it be metric. Wouldn't it make sense to use a XH box from a 78-81 Z28 as it wouldn't be metric? Am I off on this one, please help?
I already tried a 86 Monte SS box but it wouldn't fit on my pitman arm, I am guessing because the Monte box would be metric?

Thanks

 

[LS6 Tommy]

You want the metrix "XH" box. The fittings changed in 80. The pitman arm doesn't fit because you need the one for a Saginaw "800"/"four bolt" box, & you have a "605"/"round top" box pitman arm.

Tommy