Feel like 360 should have more power

Work on the basics
The compression numbers are fine for that elevation.

What was missed is a stretched timing chain which causes an engine to run "late" and contribute to the low power and probably the psi number. With the plugs out set the engine at tdc, distributor cap off, put a breaker bar/socket on the harmonic balancer bolt and rotate the engine backwards - see how far the damper moves before the distributor rotor moves....the chain will be stretched as they all stretch so ignore the blah blah blah that the timing chain tensioner does not work and install new chain and tensioner. 360's esp benefit very well when the timing is consistent. If the h20 pump is good reuse it. 195 degree thermostat as well!

The plugs need to be hotter, the timing should be at least 16 degrees btdc and a total of 36 or even more due to the elevation. Use the vacuum advance. Be sure the control box has it's own ground strap.

White smoke may be steam from combustion..are there bubbles in the coolant? Is the engine using coolant?