I have an 87 Samurai with 75K miles. Im  the 3rd owner.
 My issues are:
1. when starting the engine cold it sounds like the bottom end is coming out of it, as it warms up knocks/rattles goes away
2. Engine uses 1 qt of oil every 5-600 miles. No leaks no smoke        (Ive change the PCV valve and went to 50w oil, didn't help)
3. Ive had it almost a year, put maybe 2K miles on it and it seems to be losing power. highway hills that I normally pull in 4th gear I now have to use 3rd.

Ive checked compression . throttle and choke wide open
cyl 1 = 130psi
       2 = 135   "
       3 = 135
       4  =140
all dry checked.
I have not checked valve lash or belt alignment.
Timing is spot on with timing light
 Ive thought about rebuilding the engine or buying a rebuilt one but the plugs look good and it doesn't Smoke. Ive rebuilt several VW air cooled engines and a few SBC's but this is my first Samurai.  Ive thought about the 1.6 swap but don't want to lift it anymore. (already installed a 2" body lift)  I don't off-road so my height suits me fine.  The loss of power and oil usage has me stumped. Any input or ideas would be helpful and appreciated.

Thanks

Compression numbers are way down - you either have worn rings/bores, leaking valves, or the test was not properly done - my guess (because of low power. low numbers & oil consumption) is worn rings/bores.

Redo the test - warm engine, fully charged battery, all plugs removed, throttle plate wide open, and this time do a wet test after the dry test (add a teaspoon of engine oil through the plug hole) - if the numbers jump up on the wet test, it'll be the rings/bores - if they don't, follow up with a leak down test.