Does not compute..... If that is true, the the pistons are in no way stock, or the cam or cam timing is really hosed, or your gauge is broken. From the factory, it should be around 120-130....
So if you really have 170-175 on that LA360, then your SCR it up in the mid 10's and your cam is not very large. A Magnum with lower SCR is gonna be a dissappointment for low-mid RPM torque by comparison.
If your LA360 supposedly had stock .030" pistons, then I'd suggest trying a new compression gauge 1st.