HI. I am thinking about putting a 351w into m '67 mustang coupe since it is an easy swap with the stock 289. Anyway the guy I am buying it from says that the engine proabably has around 400 horsepower. I was wondering what mods I need to do to the rest of the car to handle that power. Can the stock c4 handle it? Do I need to upgrade to a 9" rear end. I am already planning on upgrading to front disc brakes. Anyway if you have an opinion let me hear it. Thanks

 

Ask him to provide proof of his HP claim, such as cam specs, compression ratio and other add ons. Stockers usually have less than 300 hp...

 

If the motor really has as much HP as the seller says then I would consider getting a T5 tranny. A 9in. rear isn't a must but it will handle the power better than the standard rear especially if you are going to be driving it hard.