checking deck height

how can i do this? i have my motor torn apart now and i was looking at my pistons when at tdc and they look basically flush with the deck. this is a remanufactured/rebuilt motor. would they have shaved the deck that much? how can i measure to see exactly how much space i'm dealing with here? i was thinking i could get a strait edge and lay it over the cylinder and use a feeler gauge... would this work?

A dial indicator with a base that straddles the cylinder is the best method.

Ditto on the Last.

This is the most accurate way.

I tried the straight edge and feeler gauge method, but felt there was too much variability to give me an accurate measurement. I went with a dial indicator and mag base. I zero'ed the DI on the deck then rotated the whole thing till the plunger touched the piston. I could do this until there was about 0.001 diffrence going back and forth.

There are bases just for measuring how far the piston is below the deck. Depending on how accurate you need to be will determine what you buy.