The small resevior servo unit for various GM vehicles listed below.
There is a Type A & Type B on these in real life.. check where the chain connects at the front.. both are the same otherwise but .. looks like an adjustable one (Type A Show on the upper picture) with different multiple hole spacing or the single hole as in type B- Choose.
Corvette 1990 - 96
Camaro 85-92
Chevy Trucks 83-88
Firebird Trans Am 85-92
Pontiac GP & Full Size 84-87
Fiero 84-88
Pontiac Transport: 90-91 (like Stewies...)
Most mid - late 80's Cadillac & El Camino
Type A ABOVE and rear view
Type B ..note the single pull from hole