Use the Oracle 64bit installation. A word of caution, is that oracle 64 bit may be good and sound better, but you also have to note that oracle does not come up with the patches for 64bit as fast as that of 32bit. For example, oracle had released the patchset 3 for 8.1.6 but hasn't come up with the patchset 3 for 8.1.6 64bit yet. The last patchset that came for 8i Rel 2 was patchset 1. So, you can imagine of the problem that you might have to live with for going on a 64 bit.
Life is a journey, not a destination!