Shimano Front Chainwheel FC-MC19 Replacement?
The problem is not clearance between the crank arms and frame. You need to look at the clearance between the chainrings and frame, which is likely to be much tighter.

You also need to consider chainline - how for the nominal centers of the chainrings and sprocket cluster are from the centerline of the frame. You will be moving your cranks 6.5mm inboard, that's significant. I checked the specs of both cranks [here and here] and they both have a nominal chainline of 50mm, so you need the correct spindle length to get the correct chainline. 

I think you'll probably get chainring - frame interference with the shorter axle, and I'd get a new bottom bracket with the correct axle length  to avoid chainline problems anyway. A 17 year old bracket probably needs replacing in any case.