4 plugs on underside of block??

[1991vert]

what size fitting are the 4 holes on the underside of the block, right beneath the freeze plugs? i believe they are coolant drain plugs and my machinest never put them in...

 

[1991vert]

ttt

 

[83Mustang427TT]

3/8" NPT pipe plugs

 

[1991vert]

thx brothah. are you sure you're 3/8"?