This is actually two questions
Can a 95 z28 hardtop be turned into a t-top? If so, how much?
Is it possible to turn it from automatic to manual?
To be totally honest with you, with the price you would be paying to turn a hardtop into a T-top and from automatic to manual, you would be better off looking for a manual T-top car than trying to convert yours. You will likely have another car payment involved in just the conversion. Plus, your roofline will be weakened by the removal of part of the hardtop, which provides much of the stability of the vehicle. T-top cars are typically reinforced elsewhere to make up for the loss of roof material.
Search Chevrolet Camaro Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Chevrolet Camaro Experts