will a monte ss steering box fit my 72 chevelle,napa has 1 4 $125

It will fit but you you have to get a different rag joint (new ones are expensive) and adaptors (cheap) for your hoses. You can get the kit from Lee Mfg for $87 + shipping. I just put one from an '85 MC SS on my '69 Malibu. If your '72 has power steering it already has variable ratio and probably about 3 turns lock to lock. IMO you wouldn't be gaining much with the MC box. You can get rebuilt boxes with fast ratio for your Chevelle from Advance Auto Parts, NAPA, etc., for around $130 or so. To get the full scoop on what boxes will work and what has to be done, do a search on JimL82, then the thread on "Variable Ratio Power Steering". In one of his posts there's a link to the info.