Heads up on O2 sensor location for SBF headers

[GT_Rich]

Hey guys, I am running a Holley Terminator X throttle body EFI system on a 427. I built the engine and did not start it until it was in the car (in other words, no engine dyno break in or tuning). It was not running right at all. After some troubleshooting and a call to Holley, I was told the O2 sensor position was too close to the 4 into 1 merger on the header. They recommend a 6" minimum distance from that point.

I welded on a new bung on the side pipe, in-between the ball flange and the split for twin pipes. This puts me 6.5" from the 4 into 1 merger. The difference was astounding. Engine now seems to be running right and self learning.

Just a heads up for others. If you bought a kit with a base tune from an engine dyno, they likely used different headers. You may want to turn off learning and closed loop or at least keep a close eye on it!

Rich

[Skuzzy]

Good heads up! Thank you.