Setup: look in sig...The headers on the car are 1 3/4 stepped to 1 7/8 with a 3" y-pipe into a borla cat back. Do you think the cat-back is limiting my power? Do you think true duals is a must? Camshaft is a 240/240 .600 112...

 

NO

We would expect a larger TB for a 383.

We think that your choice of tuning/ injector size/ TB size has a bigger effect on your power level. But then we don't know what your power level is???? We also don't know what size injectors your using or if the thing has been tuned. We don't know if you have a problem.

 

probably 10-15rwhp is what ive seen on the big motor between the 3" and the larger 4" single/dual systems. not enough to even feel. ive seen almost 650rwhp out of a single 3" system, so i wouldnt worry about it.