Find an enlarger you can use. I only has to cast an area of reasonably even illumination over about an 11x14" rectangle, so even small-format enlarger with a good lens should do this. Use the largest projected rectangle of light you can for the best evenness.
Originally Posted by Lodoiska
Use an 80B or 80A compensating filter (blue) to get your light source back to daylight (color heads usually have 3400K° halogen bulbs; that plus 80B and you're good to go). They are easy to find used in many screw-in sized.
Stop way down and make test strips. You don't even need holders, just position the film on the baseboard (make some guides, since you'll be working in total darkness). It should be flat enough that you won't even need an easel.
Make a bunch of exposures on 4x5 film first and send them in to be processed. Keep notes so you know which exposure is right. Then, use that exposure (and enlarger head height) to expose 8x10 film of the same type. The exposure should be the same if the film is the same, regardless of size.
You could also filter a regular incandescent bulb, but you'd need a larger filter and a lamp housing for the bulb; not impossible. And, yes, you can plug any old bulb into an enlarger timer as long as the timer is designed for the proper voltage. Check the label.