2.5 Inch exhaust to small?

[DaleTx]

X2 ^^^

My car has a 670HP 427” and makes peak power at 6,900 rpm. I ran 3" exhaust with 2.5" tail pipes at first, and then switched to 3" tail pipes. After having tried both set ups… I would recommend 3” all the way for sure. I didn’t think the 2.5” would restrict it that much but when I made the switch… there was a noticeable difference up in the higher rpm range. The engine responded well with the larger diameter tail pipes. I don’t have numbers to back this up… just seat of the pants feel. Also, the 3” tail pipes sound better and have a deeper tone than the 2.5".