Exhaust manifold tap size

[further]

What is the tap size? I believe it’s 3/8” but wanted to confirm and should I use taper, plug or bottom?
TIA

 

[Scott06]

Not sure what engine you are working but assuming it is chevy based ...3/8 -16 i believe. A bottom tap helps you get farther into blind holes so i generally buy these when getting a tap

 

[further]

Thanks. It’s a 5.0 gxi-D. Block is a Michigan motorz reman in 2015. Did some research and found someone mentioned 3/8-18 so which one?

 

[alldodge]

Should be 3/8x16 thread
If your replacing stud in the head, then bottom tap