You should be able to order the mount only from Van's. You will need to tell them what engine you have. f it is Lycoming presumably you would need the Dynofocal 1 mount, but need to confirm.
My plans indicate the part is WD-762-D1 for Dynofocal type 1 mount, but I do not find it on a parts search on the Van's site. Give them a call, they will be happy to help.
When ordering my finishing kit, I had the same question. I included the designation of my planned engine and they selected accordingly. BTW, I will have an O360-A1A.
I ordered a new 360 engine mount last year for my 7, it was 1700 Comes with the gear legs. Now Ive got a nose dragger engine mount for sale but haven't advertised it yet. I looked for a trade but it seems everyone converts to a tail dragger. Just call them and ask, they will be happy to send you one!