From everything I have heard and read, you will have either a very difficult time or very long exposures. Several minutes.
With a 300 watt bare bulb about three feet above the contact printing frame, I get exposures of between 30 seconds and a minute, without burning. When I first started contacting Azo, I tried using the flood light on a track on my kitchen ceiling. I never got an exposure time of less than about three minutes.
If you are making 4x5 contact prints you might well be able to use your enlarger light. Just be sure to take the lens out and rack the bellows up tight. That will allow maximum light through in a circle that should easily cover the 4x5. Time? Make one test strip with exposures every 15 to 20 seconds for a few minutes. That should immediately give you some rough idea of the time.
If you have the Zone VI variable contrast head, you may want to dial in the maximum blue filtration to expose Azo. Azo primarily exposes to UV light in the near UV spectrum (350- 475 nm). The cold light will probably work much better then a true tungsten source. What Michael indicated about the enlarger lens removal is helpful as well. Hope that this helps.
Just an addendum to that: it should be okay to use a diffused light source on an enlarger with the lens removed, but be careful trying that with a condenser enlarger. I did and it took a few days to figure out where the mysterious hotspot, rendered as a little grey spot under the lens axis, was coming from.
I know this doesn't apply in this case, but just for the record.
I don't have hot spots with the bulb. I do a very scientific test to make sure...I put my contact frame on an oversized cutting board that is white. And every time I set up I pull out the Pentax Digital Spot and meter the board. I put the frame in the light that is even enough to not change the meter.
Although I was just at a workshop in which we made a zone V exposure of an enlarger's cold light source with no negative, just the lens stopped down, and you could see the zig zag pattern of a cold light pretty clearly outlined in zigs and zags of more or less density on the paper. Basically, the way the cold light was rotated in its housing, it left two corners of the paper significantly lighter than the middle.
I am using an Aristo VCL 8100 cold light head to expose Azo (just the head, no enlarger, from about 3.5 feet away). Using only the blue tube my exposure times range from 2 to 10 seconds. It's fast, and easy on the eyes. This is with dense negs on grade 2 Azo from the early 70's.