17x9 and 275 tires

i have the 03 stock cobra wheels and i was wondering about what tires to go with. i saw an 03 cobra at the local car show that had these same wheels and in the back 315/35/17 . i wonder if these would fit under my 87 mustang?i have yet to get the rear axles for the 5 lug swap but there is a 98 v6 in the local junkyard that i'm thinking of pulling the parts off of.
 
i have the 03 stock cobra wheels and i was wondering about what tires to go with. i saw an 03 cobra at the local car show that had these same wheels and in the back 315/35/17 . i wonder if these would fit under my 87 mustang?i have yet to get the rear axles for the 5 lug swap but there is a 98 v6 in the local junkyard that i'm thinking of pulling the parts off of.

never tried it myself, but i dont see being able to go any wider on the back of mine with the 275's but i got coil overs and bunch of other crap
 
My friend has 315/35/17 Nittos on his 88 LX hatch... He rolled the lips, no quads or tailpipes and I think might have used a hammer on the inner wheel well. He runs them on a 17x9 03 Cobra rim.

The Nittos do run smaller though, which is probably why his works in this set up.
 
My friend has 315/35/17 Nittos on his 88 LX hatch... He rolled the lips, no quads or tailpipes and I think might have used a hammer on the inner wheel well. He runs them on a 17x9 03 Cobra rim.

The Nittos do run smaller though, which is probably why his works in this set up.

i want 315's so bad :( but no way are thye gonna fit under the stock wheel well, with coil overs, and a 95 rear axle