how to tell...
 

some have suggested that my headgasket is bad, others think it might be more serious. without taking the engine apart, what tests can i have done to check and see if it were a head gasket problem or a rings/ valve seal problem?

compression test and connect a vacume guage, if you look in a helms its tells you how to do it and what to look for

hmm, never thought to look in the book.

leak down test. that is the best to do without having the engine apart