Adding bench seats to E350 cargo van

[greese350]

We have a 1990 E350 7.3L diesel (biodiesel) cargo van. I am looking for hardware to bolt to the floor to use newer removable bench seats...

I found a pair of free older bench seats a few years ago and installed one of them (left the other one where I found it unfortunately) by drilling through the floor panel where there were re-enforced holes ready on the underside and it worked great (but I would love to be able to remove it more easily). Now we are having a second child and need a third seat. I just found a set used from a 2005 van with a hardware kit to bolt to the floor allowing the seats to be removable (like in a minivan and how I am assuming a newer Econoline works). Before I could get to see them and confirm the spacing for the bolts they were sold. I thought it would be the best of all worlds to have the seats removable (I do un bolt and remove the one I have now for hauling) and would like to pursue finding the type of hardware he was selling with his seats.

Does anyone know where I might find hardware to use removable bench seats in my 1990 Econoline?

By the way, if anyone knows of another seat for sale/trade/free in the Bay area of California let me know...

Thanks,
josh