What should you use to test your car to see if it has a blown head gasket? Is a “block tester” a good device to use for this type of test?
Last time I had a blown head, on a 1989 Caravan, the radiator guy told me to take off the radiator cap, cold, start the engine, and if the head is blown, foam and bubbles will appear on the antifreeze in the radiator.
Others will soon tell you if this works or not. 
That will work if there is a significant lek of exhaust gas into the coolant system. A “block tester” will find smaller leaks:
http://www.arrowheadradiator.com/head_gasket_or_combustion_leak_test.htm