kilhansen In the fifties for flat mount work we used coal belt,it is tuff,kind of hard to punch holes in, butwith a tuff belt punch you can do it. I have some homemade flex couplings made 20 years ago still OK. Have one my Dad made in the fifties still good. These however are not oil soaked,a racing pal said if it didnt leak oil it wouldn't be a chevy LOL !!
