Just when through the same thing
Don't worry about the cup in the middle. They make it up with a longer rod in the booster. Also Gp is full size car like the Cat.
Autozone kept giving me the wrong one so I got my money back and went to O Reilly's and the parts manager informed me it will work so I bought his and installed it and it worked.
The linkage that hooks to the pedal comes off your old booster to be used on the new one.
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Jeff
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