Schneider has info on the web about the 240 mm Componon-S at http://www.schneideroptics.com/photo...ng/componon-s/
For what its worth, Schneider recommends the max format for this lens as 180 x 240 mm. For the metrically challenged, this is 7 x 9.5 inches -- almost 8x10. So maybe it will work for 8x10, but it doesn't meet Schneider's quality criteria.
The MTF curves are plotted for a slightly larger format, but they look pretty poor in the outer 10% or so.
Since you already have the lens, it is worth keeping to try out.
Using a 240 for 8x10 is like using a 120 for 4x5, except that you will probably use smaller magnifications (print size / negative size), which will help with coverage.