How long is googles memory? Taking a previously 301'd site and making it an authority.

I've got some expired domains that I will eventually build into a private network.
I'm looking for a boost for the Christmas season for a ecommerce site.

If I 301 redirected one of the domains now, and then remove the 301 in few months and build blog on there, will Google pay attention? Would they really dedicate that much computing power to checking this stuff?