Finally got in the garage and compression tested my cars 1972 400cu-in engine, factory 8.2 to 1 compression as far as i know, 128,000 miles.
I thought i may have a bad timing chain, have not pulled timing cover yet but am 1/2way there, block drained, etc - previous post here --https://board.moparts.org/ubbthreads/showflat.php?Cat=0&Board=QuestionAnswer&Number=7783679&Searchpage=1&Main=7783679&Words=+ignoble&topic=&Search=true#Post7783679

So a test showed on the gage 148-135-138-132-131-135-140-125 psi. Is the rule of thumb 10% variation or more, is too much difference? With only cylinder #1 still at a high psi#, i wonder if its time for a machine shop evaluation or other plans in addition to a probable loose chain ? Thoughts ? Thanks.