Just wondering if anyone can assist me in verifying the authentic look as well as casting number of the original assembly line power disc brake master cylinder? I know what a 1970 E Body 2229171 casting number power disc brake master cylinder looks like, but it is round in the front and has the thermostat looking outline on the front of this rounded end. The 1970 Polara C Bodies I have seen with power disc brakes have a similar look to the master cylinder but are rounded towards the firewall. Is the rounded towards the power booster or firewall the correct look for 1970 power disc brake Polaras? I think the casting number on the bottom of the 1970 power disc brake master cylinder should be 2225621 but am not 100% sure. Thanks!!!!!