To go back to the simple things:

1) Is the compression gauge well seated into the sparkplug hole? Does it seal with an o-ring? Is the o-ring in place? Is the o-ring in good condition.

2) Some of the sound you are hearing *may* be just the inherent slack that exists in an engine. 20 year old engines have more slack. By the time you add up the tiny bits of slop in the mains, the rods and the pins, sometimes it makes a lot of noise. I blew a gasket way back when and the darn thing sounded like it had a bad case of rod knock. That is with the bottom end being good in retrospect, but the free spinning of 3 pistons and the resistance (gauge) on one can make things rattle.

3) What did (does) the oil look like? Did it ever get milky? Does it have a pretty sparkle to it? Chunks? We are back to assuming the top end is OK and there is something in the bottom end. A cracked block will not make noise (per say), but a toasted (like really toasted) rod bearing or wrist pin might. (I am really stretching here for ya).

Again, share the compression numbers you are getting. They should not be the same as before a head job and a new gasket unless you are a) really unlucky b) you are doing something wrong when you are doing the compression test.

Good Luck,
Michael