The academic rigor for the EMBA program is generally the same as that for the full-time program. To that end, both AdComs will seek candidates who can credibly demonstrate that they are ready to undertake the academic challenges involved with the Wharton MBA curriculum.
A 66% quantitative subscore would, by itself, raise concern with AdCom. AdCom would then look for other evidence of quantitative ability. Depending on the nature of the courses you took, your performance in those courses, and the type of work in which you engaged at a Fortune 500 company, you might be able to make a case that you are still ready. However, you would have to make this argument somewhat explicit and clear with good, tangible examples. There is also the underlying question of, if you are strong in your quantitative abilities in the past and in your work, then what caused the 66th percentile subscore?
In terms of odds, the only thing that can be said with certainty is that, if you don't apply, your chances of admission are a guaranteed 0%. Please see http://engage.wharton.upenn.edu/MBA/forums/p/3282/9399.aspx#9399.