i believe one head stud hole has to be drilled out a bit more for oil passage. the rest are drilled out to 1/2inch. buy a new drill bit. i have ran a 2g head on a 6bolt from day one of m dsm life. some say its the way to go. i used the 6bolt T housing and water pipe. this was in a 1g so cas wasnt an issue .. now its going into a 2g so i will be wireing in the 1g cas.

i used a 2g throttlebody with custom sensors for my 90.