Actual ZL-1 Horsepower.

[SMGCO]

I don't think there is any comparison between the old OEM chambered exhaust and the gmmg chambered exhaust. The old exhaust was crimped at the bends and was down to less than 2" in many areas. Our gmmg exhaust is mandrel bent ( ie, smooth bends ) and fits perfectly. Call Murphy and discuss it with him. He thought everything on our cars through with ultimate performance in mind. However, you might want to talk to Porterfield out the dual cutout he has on car #1. Barry at Quick Time Performance can help you also.
What rear end gear ratio do you have in your car ? The 4.56's in mine really woke it up. Any more power and getting traction is not possible without drag radials or dot slicks.

Regards, 02-#47 zl1 ( c5r )