Tire Width Differences in Performance

[GT408]

Hello all. I'm currently in the design stage of a 1966 Mustang Fastback that will be built with some modern day Pro-touring style in an effort to be unique in styling, but more importantly to improve handling. I'm building a modest 408W and am shooting for 500hp, nothing too crazy. One day I might install a 4-link coilover in the rear and coilover in the front. But in an effort to get the car up and running while not waiting on the extra $5k difference to invest I'm going to start with leaves in the rear with sub-frame connectors along with some chassis modification to improve rigidity, and improvement of the front end geometry. My question is this: has anybody experienced, or can anyone honestly tell me if they see a valuable difference in running a F275 R315 set of tires versus a F245 R275 set of tires. The first set of numbers is the tire combo I plan to run with a 17" rim, the second is with 16". I might also consider R295 with the 17".



I don't plan on being the fastest person out there, I don't have the time or money to allow a full dedication to becoming competition worthy, but I would like to be able to build something that allows me to have a good time and turn some decent numbers in performance. Second thing is, if I go with 315s then extensive body mods to the rear will be in order to fit that width...mini tubs and stretching the fenders...all which I am willing to do if it's worth it since I will be doing some body modification anyway. I just don't want to add a whole lot more work for a minor difference in performance. I want to get up and running sooner than later! Thanks for the input.