What size cam plug do I need for back of block

[Full Size Jeeper]

Picked up a 2 1/8 and it would not go in, bent it up. so I looked it up and found a few people online saying the correct size plug is 2 9/64.that is bigger than the first one I tried. Someone help me out. Maybe I don't know how to put one in, even though I have put in a bunch of expansion plugs over the years. next size down from 2 1/8 would be 2 /764th.

[johnsonic]

I used this guy: Crown Automotive J3172313 Camshaft Plug https://www.amazon.com/dp/B009XV0GLK..._HSE9Cb1QZYFHQ

It’s 2-9/64

Should note it was for a 360, not sure if a 401 is different.

[rang-a-stang]

Mine came in a kit. My machinist told me to get a plug kit. I am pretty sure this is the one I ordered:

https://www.amazon.com/Sealed-Power-3818001-Brass-Expansion/dp/B000C7JH8C/ref=sr_1_1?keywords=SEALED+POWER+3818001&qid=1559973135&s=automotive&sr=1-1

It has all the freeze plugs and 4 of the galley plugs (you have to buy 2 more galley plugs). Kit says the part number for the cam plug is 3813084 which Rock Auto also has for $1.09.