Question about codes

I am getting everything ready for my mass swap this weekend and wanted to see what codes were present with the SD comp

KOEO
81
82
85
84

KOER
41
91
33

The guy I bought the car from removed all of the smog stuff including the purge canister, along with the vacuum stuff for the EGR. So the codes that pertain to the smog stuff I am not that concerned about, i am however concerned about the 41/91 codes, will a non-working egr cause or create a lean condition? i have done a search, most of the people that have posted these codes are running mass, should I wait to put the conversion on and then re-run the code test to see if I still get them or should I try to fix the lean condition now. Mods are in sig. I am pretty sure that the SD computer just isnt able to adjust for the larger intake and exhaust. Any Help would be greatly appreciated. Thank You

-Josh-

ok after reading through some of the other threads I checked the ground wire on the back of the heads, it was loose very loose so I tightened it and re ran the codes cleared them and then I checked them again. 41 and 91 are gone but I got a 21 on KOER what is that about.

Thanks

-Josh-

ok that kinda makes sense then cause the car wasnt completely up to operating temp when I started the test. I will check it again later just to make sure.

Thank you

-Josh-