Is synthetic oil good for my 1987 ford mustang gt convertible?

YES, YES, YES!!! Synthetic oil is good for ALL cars!!!!! It keeps the crankcase cleaner, removes dirt as you drive, can handle heat and stress better, and only needs changing once every year or so. I recommend Mobil One 0W-30 for you. You save gas, too. Forget regular oils. Pretend they don't exist!!!