how many quarts of fluid in a powerglide 1966??

If it was just drained, it about 3 1/2 max, if the torque converter was drained also it will take a total of 10 1/2. don't over fill. Put 2 quarts in, put in neutral run until warmed up and add about a quart and a 1/2 untill it shows full on the dip stick. If replacing converter with new fill converter until you can stand it on its side without fluid running out. Hope this helps!