I need a new Master Cylinder for my brakes for my 1987 Nissan pickup. do I have to buy the specific or will a different model work. also which one will work.

You will have to buy one for that vehicle. Suggestion: Call a couple auto parts store and price them sometimes there can be a big difference in price and higher price doesn't always mean better product. Also price new one and rebuilt sometimes the new ones don't cost much more and a new is better then rebuilt but if new is lets say $450.00 and rebuilt is $265.00 I would get the rebuilt but if there is only $50.00 difference I would get the new one. Don't rule out dealer they did drop prices to compete with aftermarket parts to bring sales up. You can also get prices online anymore at some parts houses. Autozone has good listing.

You have option of different brands from different vendors NAPA, dealer or auto parts stores but they will have same basic master cylinder. They have to look part up by application. Shop around for best price and warranty.