Mine are open down about 4 inches then just stop. I'm hesitant bout openin up the holes if they DON'T go straight down.
Hate to add n new set of heads to my need list.
BTW still lookin at my temp guage problem, Worked twice for about 5 miles down the road, then back to cold setting,
So now I ASSUME guage, sensor, wiring, 7 V reg, are in working order.
Stumped in Northern Mi,

Dan