I just built a new big block for my tow rig with .30 over flat top pistons and a isky cam (duration 262 lift .488) along with intake and headers. I kept all my sensors and the tbi. I've put almost 100miles on it and its runs great other then the O2 sensor is not getting warm enough so its wanting to lean it out
I welded the O2 bung in the collector of the header here's my question if I have my headers ceramic coated will that make them retain enough heat or is ther some other trick I need to do? I think I'll wrap my header up with some heat wrap and see if it makes a diffrance.

I don't know

I would deffinatly wrap them with header wrap first just because of cost and down time envolved with getting them coated. You can also get "Heated O2 Simulaters" they make the ECM think its running in ideal conditions without haveing O2 sensors.

How about using a heated O2?

Just go with a cheap 3 wire O2. It will have 2 wires for the heater and 1 for the sensor like normal.(2 blk, 1 white)
Just hook 1 wire to 12V when the key is on and the other to ground.
They only draw milli-amps of current.

But the O2 getting cold(at idle) is not what is making it go lean.

You need to tune your chip to match the new engine combo you now run.

The ECM will not use the O2 data unless it gets up to temp and produces 600mv.
But when you idle the temp drops and the O2 cools off. The ECM will then go back to open loop mode just like when you start it in the morning when it's cold.

Hopefully your sensor is also on top or the side of the collector.

I recommend you log data with a laptop and see what your fuel table is really like. Then you will know what needs adjusted.

The overlap in the cam will dump raw fuel in the exhaust and the ECM will try to lean it out.
You will start to get a lean roll at idle.
Most factory BBC's are set to go open loop below 900rpm.

its giving me the code when the engine is up to running temp and turning about 2500rpms then when I pull the plugs they are white

asfar as tunning with a lap top this is in an 88 crew cab so its obd1

dose any one have a part# for that 3 wire O2 and a diagram

I just got back with some heat rap and hose clamps so I'll see if that helps

its giving me the code when the engine is up to running temp and turning about 2500rpms then when I pull the plugs they are white

asfar as tunning with a lap top this is in an 88 crew cab so its obd1

dose any one have a part# for that 3 wire O2 and a diagram

I just got back with some heat rap and hose clamps so I'll see if that helps

Did you try to click on the link in my sig????

Nothing wrong with heat wrap but you just wasted money.

The ECM is only capable of adding about 10% deviation to the fuel tables.
If you are throwing an O2 lean code then you need to tune it.

And again I would recommend you read a little in the FAQ's at the link.

I run the same type system you have.

I just built a new big block for my tow rig with .30 over flat top pistons and a isky cam (duration 262 lift .488) along with intake and headers

If you made all these changes to an engine with a carb...would you think to rejet the carb if it was lean??????

So what is the difference with FI.
The system still needs to be adjusted to compensate for the changes.