I have a 1965 mustang. I wanna put a complete braking system off a 1988 mustang on it. My question is ? Is it possible and what all do I have to do to make it work

 

If you have a V8 1965 Mustang, there is really no difference between 1965 and 1968 V8 brakes. If, however, you have 6 cylinder suspension, here is what you must change:
Rear axle assembly from a 1965-66 Mustang - complete
If you have a std tranny 6 cylinder, you must locate a 67-68 6 cyl front yoke and a 65-66 V8 or 6 cylinder A/T drive shaft (the 8" rear end uses a larger yoke)
If you have an A/T 6 cylinder w/A/T, your present drive shaft will work okay
Replace the 6 cylinder stuff to the V8 stuff for 1965:
Idler arm
Pitman arm
Center link
Inner tie rods
Tie rod sleeves
Outer Tie rods
Spindles
If you install a V8 motor in place of the 6 cylinder, in addition to the above, you will have to replace the 6 cyl coil springs to V8 coil springs
From the 1968 donor car you can use the following
Front back plates, drums, shoes, hardware, hub, wheels and tires
Rear back plates, drums shoes, hardware, wheels and tires.

You should be able to use your 6 cylinder park brake cables
Best,
Al