The first 5.9 Magnum engine in my buggy went boom shortly after hearing aticking sound like youre describing.Im running a 727 trans also. I could hear it behind the air cleaner and sounded like it was under the intake , like maybe a lifter.I replaced the lifters ,worried that they may be wore with 220,000 miles on the motor.
The ticking was still there , flogged it a few times in the drive way and hit it once in reverse and blew #3 and #4 rods clean out of the motor.There was no vibration or anything , just a tick.And then shazam , all at once split second vibration and then oil and coolant covered the drive way.
Not telling you this to scare you , just interested to see what you find out.At first i thought mine was too many rpms and too many miles on the motor.