Will these sony xs-w1620 6 1/2 2way speakers fit in my 87 bird?

 

Where do you want to put them? The stock speaker sizes are 4"x6" under the dashboard and 6"x9" in the sail panels.

 

Where ever I can fit them easiest.

 

You could either run those in kick forms or in the sail panel location (providing you have kick forms or are looking into them). I seriously doubt that you'd get them to fit into the stock front dash location without some serious modification due to the HVAC ducting and ECM mounting location (if F.I.). The easiest mounting scenario would be the rear sail location, if you wanted to use them back there, but it would still require some fabrication with either MDF, aluminum or fiberglass. This all depends on what you want to do and what you feel comfortable with. Since I am not sure of what you are experienced with or what you want to do, I've added some links below for some stuff.

http://www.crutchfield.com/p_044C100...res-Black.html

http://www.crutchfield.com/p_142SA69...-Brackets.html