I ran my car this past Wednesday at E-town, and made 2 passes with my normal setup, and then 2 passes with open headers(actually open export pipes since I have no cats right now). I ran 2 mph and 2 tenths faster with the open headers(all times and mphs were improved upon and the 60' times were the same, might have had some spin but couldn't hear it with the loud exhaust, so there is no loss of bottom end as far as I can tell), but I am wondering if I was getting any timing retard from the very loud exhaust. I don't have a scanner, or LT1 Scanmaster, so did anyone ever try this and record any results?

I want to know if getting the least restrictive catback out there will cut back on the sound, but give me the flow I want. Do you think that I can pick up even more if I had a little bit more back pressure? Anyone who has tried this please post your results. I still have the stock catback exhaust, and I now know that you can go faster with almost no back pressure. So what do you all think about this?

One small item, this is on my 96 Impala SS, but the idea is the same between our cars, and I still have the LT1 ESC and knock sensors since I don't trust the LT4 ESC mod yet. Thanks for any input, and this was with a stock converter, so I am very happy to see that my bottom end wasn't lost due to no/low back pressure. Just wanted to share this with you LT1/LT4 guys since there aren't alot of guys who run open headers anymore.

 

My friend and I just put long tubes on his 94 LT1 Z28 and they are currently open. He has a scan master built into his dash and I have an autoXray and he gets away with no knock.