yes it will
Nope
yes
Yes, both should be interchangable.
not today.
yes
yes it will fit
5 quarts
Yes. It is a direct fit. Nissan didn't change the rear hatch and they are interchangeable. 1984-86 won't have the third brake light. 1987-1989 will and you'll have to wire that in if you want it to be operable.
15.4 gallons
Nope sorry it doesn't have a 9" rear... It's an 8.8 integral rear where the 9" has a removable carrier aka: pumpkin... I only wish my 1989 Mark VII had a 9" because it was an still is a bullet proof rear!!! I had to rebuild mine once and it is in need of another rebuild. I wish I had the money to fabricate a 9" into my Lincoln I would have done this a long time ago... They do have housings for the Mustangs of this era but the Lincoln is wider and a little different then the Mustang...
I Hurd that the 1985 mustang gt top speed was 135mph so the 86 shouldn't be slower
Depends most likely a 256 or a 272 I have seen both if its two wheel drive.