Can anyone tell me if the 5.4 has a 1-3/4" or a 1-49/64" freeze plug? I measure them and they seem like a 1.75" plug but I've seen a few old posts that say they are 1.76 and that people often install the 1.75" by mistake and they leak. Any ideas which it is?
I can't find a brass freeze plug kit anywhere for the modular fords.....

 

1-49/64" = 1.765625 So, about a .016 interference fit sounds right.

 

OK, another question.....
There are two small one's that are 1.5" diameter. What size core plug would go in those? Any idea? I'm not sure what the next size above 1.5" is? Just add the same .16" to that measurement?
I'll probably just end up ordering them from Ford as bad as I hate to.....Just to make sure I get the right size.