O2 on a TBI with LT headers

[warbird]

i have a 94 GMC 2500 2wd with the 5.7 TBI i am putting LT headers on it (heddman i believe) i was wondering what everyone does with the O2 sensor? i am planning on running the 2 headers with 2.25 pipe back to just past the tranny then have them come together into a 3 inch collector then going single out the rest of the way. my question i guess is will moving the O2 so far downstream from where it was originally will this cause negative side effects? . or should i weld a bung into the header on the pass side and just put it there? however this would mean it is only sampling from that bank of cylinders and im worried that would have negative side effects........ any input/ideas?
thank you

 

[GMstrong]

IIRC the tbis only have one o2 on the driver side simply drill a hole in drive side collector and weld a bung like you said.

 

[DRAGGIN95]

I would use an O2 sensor downstream in the collector, but you need to swap to a heated O2 sensor to do this and have it work correctly. The reason that most 87-94 V8 TBI trucks have the O2 sensor in the exhaust manifold is so that it gets heat from the engine for a cleaner A/F ratio reading since they don't have a heated O2 sensor, all the 1 wire O2 sensors have no heater built in them and if you move them away from the engine much at all they won't read worth a crap. I have swapped numerous 87-94 trucks and suv's over to the heated O2 sensor, you can use 95 V8 TBI heated O2 sensor if you want, or newer, on the 95 it is simply 3 wires 12V ignition on power, ground, and signal which hook's to your original 1 wire system, some of the 87-94 4.3 TBI engines came factory with a heated O2 sensor. Also you will see faster warm up and idle rev down, with a better A/F ratio with this swap.

 

[great white]

yup, 3 wire heated O2 sensor will let you put it pretty much where ever you wish.