Compression gauge?
 

I searched through the forums and couldn't find any related material. My question is...I'm supposed to be buying an rx7 with a relatively freshly rebuilt engine. Just buying the car for the engine but wouldn't mind having another car for parts and plus he only wants 200 more for the whole vehicle but the body's trashed...I want to give the engine a compression test before I put money down on the table so I was looking to buy a compression gauge. Neither mazda or my local large tools store have a rotary compression gauge so what I'm asking is whether I can use a regular compression gauge or will it give me faulty results. I know that the reading's going to need to be adjusted but will it work? and if so what sort of readings should I be getting that would make it a good engine? If anybody could give me a chart of readings and life expectance with each reading that would be great. Just read the sticky and wanted to add that it is a 2nd gen...87 RX7.