1st of all sorry for the double post, wanted to add some more su tried to push stop, must notta worked. im not so sure of tire size yet i know i want to run 18s on the back and 17s on the front. i do not know the exact size because i have not decided about flares etc. the rear i will order will probably be 50 inches instead of the typical 52 so i hope to get some more dish to it. i amy also put some minni tubs into it depending how the 4 link mounts.

 

I think you need to put more thought into the rear. The 65/6 is obviously the smallest of the mustangs and very tough to get things into. Going 700 HP in a street car requires very significant modifications to many/most/all of the structural elements. You need width in the rear or you will sit and spin or worse turn left unexpectedly when you gas up the throttle .

You are also adding significant weight to the front end which will result in increasing handling imbalance the cars had stock. I think you should spend some time weighing options to lighten the front to try and gain some of it back. You also need to consider how wide of a tire you want on the front.....anyway I don't want to preach...I could go on all day

Here is an example of a purpose built high horsepower mustang as it is being created. The owner was looking to build a budget high power pro-touring style car that would be able to generate the HP levels you saying you will have and also have the car able to handle the power in straight lines and around curves
http://troyboy468.smugmug.com/galler...7_HN3dp#P-1-16