First a little background info.
I removed the Crossfire eng and installed a L98 from a doner car I bought.
The L98 was knocking so I rebuilt it. It's now a 383. See sig for other mods I made.
Main problem is the BLMs are 108 from idle up to abt 2500 RPM during cruise (haven't cruised over 2500 yet).
I've tried everything I can think of to bring them down.

I've tried changing the inj constant from 24 to 25 to 26 to 27 to 28 to 29 but the BLMs are still at 108.
I can get the idle BLMs up to 128 if I reduce the fuel press to 12 PSI, but that is waaaay too low for a TPI.

The really strange part is when I pulled the plugs, they are tan on one side and white on the other. It's definately not running rich.
Someone mentioned a vacuum leak could do that, but it seems like the BLMs would be high if that was the case.

I got a code 43 twice this week. Replaced the ign module thinking maybe an intermittent mis-fire could cause the O2 sensor to read high. Haven't seen the code 43 again, but the low BLM issue remains.

I'm totally stumped.
Any ideas??