Can new O2 sensors make your car run leaner/richer?

I recently had installed DENSO 3 wire heated O2 sensors in my LT1 and a DELTEQ, replacing the single wire BOSCH sensors that my tune was done on.
The reason I did this is my 93 LT1 has a LT headers and a medium cam, 230/236 XE in a stroker motor.
The tune was very good before, just the idle was burning my eyes because it wouldnt stay in closed loop. The Heated O2's fixed this.
The dyno before today was 425 rwhp 428 tq with 12.9 AFR and now with the new O2's its running 14 to 1 AFR! and making 396 rwhp and 365 torque.
Also, the second Dyno was different from the original place and the Wideband was placed in the tailpipe of the second run (which had lots of balck smoke) while the first dyno was in the bung right after the collector, but no black smoke.
On the road when I floor it it does the basic black smoke puff intially then there isnt any black cloud.
MY BLMS at WOT are 128 and the O2 sensors are 850( plus or minus 10 points) area at WOT, 36 degrees timing and no knock. FP 43psi with vacuum line disconected.

Anyone???

On this link are my dyno AFR graphs
http://i33.photobucket.com/albums/d80/Steve40th/17803133514.jpg
http://i33.photobucket.com/albums/d80/Steve40th/17803123722.jpg
http://i33.photobucket.com/albums/d80/Steve40th/17803112939.jpg
http://i33.photobucket.com/albums/d80/Steve40th/17803090810.jpg
Steves dyno and these are with heated O2's and DELTEQ, and the videos are from other cars there.
here is my old dyno graph across town.
http://i33.photobucket.com/albums/d80/Steve40th/Dyno-StevesLT1.jpg

The car is in open loop when you're at WOT, so to simply answer your question, no.

And on a side note, I would recommend you find somebody to give you a second opinion on your tune, or to at least scan it for you to see what's up. Running that kind of AFR with that timing isn't likely going to make the motor very happy.

The car is in open loop when you're at WOT, so to simply answer your question, no.

And on a side note, I would recommend you find somebody to give you a second opinion on your tune, or to at least scan it for you to see what's up. Running that kind of AFR with that timing isn't likely going to make the motor very happy.
The tune that shows on the latest dynos is the same as the tune in the last graph. The only thing changed was the Opti to a DELTEQ and unheated O2's to a Heated O2's. The tune was revised for the idle, to compensate for the heated o2's actually bringing it into closed loop as it wasnt at idle before.
I am trying to find out what would cause the car to run like this on the dyno. The dyno is in the same town, and the difference is the above noted items I changed. But on the road there is no spark knock, ignition retard and my O2's are around 900mv, blms at 128 at WOT.
I am wondering what was different on the dyno.