I understand now. It seems 734 binaries path overriding 817 binaries path. You can troubleshoot later your path. As work around set ORACLE_SID and go /O_H817/bin and try to trigger 817 binaries from there. you don't need to set your path if your local dir path is /O_H817/bin.
To be precise, you don't need to have the ORACLE_HOME in your path. When you set ORACLE_SID and export ORACLE ENVIRONMENT by sourcing(C shell) /by exporting(K Shell) it checks and validate oratab and picks ORACLE_HOME from there.
You see my C-shell profile and how simple it is:
apps% more .cshrc
# @(#)cshrc 1.11 89/11/29 SMI
setenv LD_LIBRARY_PATH /opt/SUNWspro/lib:/usr/lib:/usr/openwin/lib:/usr/dt/lib
set path=(/opt/SUNWspro/bin /bin /usr/bin /usr/openwin/bin /usr/sbin /usr/ccs/bi
n /usr/ucb /opt/SUNWspro/bin /etc .)