multiple O2 sensors

[Don.F.Broadus at ucm.com]

Take a look at the JUNE 1999 issue of Chevy High Performance magazine. On
page 83  is a photo  of John Lingenfelter's 357 cube
race truck engine. There are  O2 sensors in each header tube. Only the
passenger side is shown but it is likely the driver side header has 4
sensors also. Two Holley 750 dominators feed the engine. Pi Research  on
board data acquisition collects all of the sensor data. The article does not
reference the O2 sensors and they appear to be at least 3 wire types. Has
any one seen this set up before ?   
                   Don