Can anyone tell me the width backing plate to backing plate of the 90 tbird? I am getting a different car as the tbird as turned to crap. So I want to use the rear end out of it for the 49 ply. I need 58-59" backing plate to backing plate or close to that. Is the tbird a close fit? I can't fiind any site that has the measurements and the tbird is at the shop right now.