I am building a new motor for my procharger F1A and needed some help. I have hooker LT going into a mufflex y-pipe, will a 4 inch mufflex cat back be enough to make 1000 horse power, or should I just go to a 3 inch dual.

 

I have the same exhaust but only put 568whp...lol,
but I have a friend of mine who put 1043whp on a single 91mm turbo no cats tho..lol
I belive he had 4'' down pipe, then connected to the mufflex cat back.

 

i ran the mufflex for awhile, and my main complaint with it was the weight. but they sound awesome and arent all that loud. it would be easier to hit the 1k goal with dumped bullets and the car would carry less weight, but would be louder.

 

I would go bigger if you could. I saw less backpressure with dual 3" over single 4" at 700 whp. Now at 1018 and dual 3" is being worked hard. I would go dual 3.5" if possible to fit but you can get there with 3"