I't important to know exactly your desired installation, because tinycore64 could be simply a matter of adapting your current installation.
these options are available
There is an http://tinycorelinux.net/7.x/x86_64/release/TinyCorePure64-current.iso
if that's what you're looking for?
boot to it and download tc-install extension and any other extensions you desire.
Note: Extensions for a corepure64 (64 bit kernel and 64 bit user-space applications) installation requires a dedicated tce extensions directory, especially if co-located on a drive alongside a 32bit tinycore or tinycore64 installations. It's repository is separate from the x86 and x86_64 (tinycore 32bit kernel and 32bit user-space applications & tinycore64 64 bit kernel and 32 bit user-space applications) combined repo.
Or If you already have a tinycore frugal (default) install, then
for a 64 bit Kernel with 32bit user-space applications you need only to add
to your boot directory and
add an option to your boot config file to use the above
Depending on your hardware you may need to download hardware specific kernel x86_64 module extensions
it's all fairly straight forward and easy