Working on my late fathers 70 challenger. The master cyl is leaking fluid inside the car. When looking at replacement masters all the ones that look like the one on the car are listed as power 4 wheel drum. The car is a manual 4 wheel drum. I remember my dad putting a master on the car a long time ago, possible he got the wrong one? I was going to rebuild it if correct, replace if not. Thanks for any info.