Books say compression is s'posed to be 8.2. Question is 8.2 what? My gauge has psi in ranges of 10 and kPa but I'm confused as to what I'm looking at.

 Jim

8.2 is the mechanical comp. ratio. It has to do with volume/length of stroke, piston design(dished/flat/domed), and chamber volume. It has no bearing on checking the actual compression, with a gauge.
To check comp. with a gauge, screw the gauge into the cylinder, disconnect the coil wire(or the red wire on the cap, for HEI), prop the throttle all the way open, and, for the best results, remove all of the sparking plugs. Make sure the batt. is fully charged.
With the gauge in, crank the engine at least 5-6 complete turns(revolutions). The more, the better, but 10 or more is redundant. Check the reading on the gauge, and write it down. Then move the gauge to the next cyl. and do it all again, repeating with each cyl., until you have done them all.
What you are looking for, is a major difference in the cylinders. All of them should(in a perfect world) have within 5-10 psi of each other. If you see one(or more) that is way less than the others, then there is a prob. with that cyl. That could be a valve, head gasket, rings, or piston problem.
You are not looking for a certain, specified in the book reading. Most healthy engines will have approx. 125-160 psi on a gauge. Some may have more, some less. What you are looking for is an average between YOUR cylinders.
Lets say you have 6 cyls. with 120psi, and 2 with 90psi, or so. That is a big enough difference in two cyls. to warrant an investigation. But, if all of them have, say, 110psi, then all is well, as they are all within the range. It doesn't really matter if all cyls. have 125psi, or 75 psi. If they are all the same, or very close, then all cyls. are sealing.
The mechanical comp. ratio will have a part in the overall max. psi, as a higher comp. ratio will give you a higher psi reading on a gauge, but it would still need to be the same psi on all of the cyls.
Does this help, or are you more cornfused now

Nope...thanks...that about covers my questions...need to keep this around for others to learn from.

[QUOTE=Adams' Apple]for the best results, remove all of the sparking plugs.  [/QUOTE]

I know it's a pain to remove them all... but isn't it highly recommended  to remove all plugs as compression can bypass from a good to a bad cylinder with a leaking head gasket, and make it appear higher than it actually is?

2 cruzn38732.6120949074

You are correct, sir!! I guess I should've made that a little more plain/clear. Sorry!    

 Here's the deal. ie. why I'm doing this. I can only do one of two things...paint the car or replace the engine this year so far...so if the engine tests good...I'll hold off for a while and just work on getting it set up right....

 Wife gave me a choice...

Good strategy Jim!

[QUOTE=JimG]

 I can only do one of two things...paint the car or replace the engine this year so far...so if the engine tests good...

[/QUOTE]

 Seems to me the engine was fine when we were on the Sky-Line... you didn't have any trouble getting down main street...   or up the mountain...

It's burning a tad bit of oil... and it's lethargic as heck... besides I need to keep up with you big HP vettes...

If you find a cylinder that's low, squirt a little oil in there and try again. If the reading goes way up it's the rings not sealing. If it stays the same it's the valves leaking.