set y-axis length on chart imported from excel

With PowerPoint 2007, in 2003 Compatibility mode
I've inherited a file with two slides with similar simple 2-d column
charts that apparently were imported somehow from Excel (I assume this
because when I create fresh charts the tools are completely
different). With both, the object that contains the chart is sized
5.16h x 8.5w. on chart A, the y-axis scale is 0-5000, on B it's
0-4000, with major units at 1,000 for each. With A, the actual length
of the y-axis is, let's say, 5". With B, it's 4".

I want the actual length of the two axes to be the same. If I stretch
the object vertically, or stretch the plot area vertically, every
character on the chart, whether text item or numeral, also gets
stretched vertically. I want the length of the axis to change, but
not every character on the chart. Is there any way to do this?

THANKS.