I have a partnership with another man to install flooring. We both have identical Vans which we personally own and use exclusively in our business. Can the partnership purchase the vans from us and take a deduction for the ecpense as they would if they bought the vans from a dealer?

What kind of partnership? Corporation, d/b/a?

... Can the partnership purchase the vans from us and take a deduction for the ecpense as they would if they bought the vans from a dealer?

Certainly. But check with your tax preparer. It may be that you will have to depreciate the van over several years, instead of deducting the price all at once.

It is just a straight general partnership filing on form 1065. We do have a unique name we use but I don't think it is a dba, just the name of out partnership...