ok for starters, i have done some research.

The Problem : zzp header/dp with no cat and basically straight piped(baffle in resonator broke and was cut out) with a muffler that we had off a 65 mustang. The exhaust is very raspy and vibrates badly, also had to replace 3 gaskets so far on the phlange after the dp. almost forgot it throws a CEL but no big surprise there.

The Answer : been searching some catbacks and i think im gonna go with a megan catback and gonna get a new dp from zzp that is catted.

The Questions : the car doesnt seem like its getting enouch back pressure and im wondering if i get the dp with a cat would there be a big performance loss as apposed to the no cat dp?

Would it sound better with no cat and the megan exhuast or would it still be raspy?

 

It will be raspy regardless. Its the nature of the beast, unless you are turbo. There will not be a big performance loss as the cats of today are more advanced than the ones of years ago. It will cut down on the raspyness but it will not go away. Megan exhaust will still be raspy with no cat.

 

yep had a megan and it was a bit raspy have a borla now and still raspy at times. btw im catless