Hey all new guy (Jay) on the forum here.. and I need a couple of thoughts. Firstly just a fill-in I've spent many years wrenching including 4 yrs on C5 aircraft in the A.F...three years machining for aerospace... and I'm a certified welder. Although there's always tons to still be learned there's not too much I find to be daunting but you all know the Ranger platforms and I am uneducated in the way of the Ranger...so alas I am again a newbie haha. Anyhoo...the highboys have always caught my eye as they epitomize (to me) how a brute truck should look. The opportunity has come up for me to pick up a 76 for 500 bones. Got her running and idling...test drive was decent..however there is one concern. At a certain rpm...maybe 2200, there seems to be a grind or low growl every second or so from the engine bay.. "rung rung rung". Doesn't do it at lower or higher rpms which seems odd. The truck has been sitting 7 years so I'm pretty excited just to have gotten it started ha...and it has a newer distributor and wires...along w new mufflers. Anyway I know it's tough to describe and I took video but can't hear it on there very well. It sends a vibration into the cab. Is it likely to be a crank or harmonic issue? Or more likely to be a misfire or timing? How would one troubleshoot this? Thanks