I have those gaskets in stock and just went and pulled a set. Although they are still in the plastic, they measure 4.150, closer to 4.160 ish. Non compressed about .034, so I am sure they will compress to about .028-.030.

I cannot say for sure that they are Detroit gaskets, as I didnt even think they were still in business. I believe they are repackaged ROLS from Mexico. I will do some research to get the correct information on their origin.