gm 3100 v6 to gm 3400 v6

[sea_of_glass2003]

I have a 99 chevy lumina with 3.1L/3100 v6 L82 engine vin 'm' and it started knocking so i was told I could drop a 3400 v6 to avoid more problems with the 3100 series and wouldn't have to change much. My question is what 3400 v6 engines would match up easily to my car? Would I be better off with (LA1 OR LQ1)?

[sea_of_glass2003]

Ok now I was told to forget about the 3400 and go with the 3500 I am so confused as what engine to get

[bszopi]

If you go with the 3400, you will want the LA1.

If you go with the 3500, you will want the LX9, not the VVT version.