To be quite frank, it'* just as the title says. My motor had a spun rod bearing and seized and I need to swap the motor out. I found a used motor with the same amount of miles (120k) from a GTP. Should I be concerned about anything before buying the motor that could not work for my SSEi?

The engines should directly interchange. The year of the donor will dictate what all needs to be swapped over to make it work. Make sure to take the time to install all new gaskets on the donor before putting it in, as that will be the easiest time to do everything.

As a follow up, I'm heavily considering on buying the motor. The guy I spoke to is a specialist (supposedly) and builds up these motors all the time. The motor I saw in the Craigslist ad sold but he can get a '04 impala SS L67 block with 130,000 miles (10,000) more than my car. Any suggestions as to what I need to look at other than the motor stamp, if it'* in the car hear it rev etc. My concern is mainly if the motor is out of the car already and since my last motor spun a rod bearing and seized after getting a fresh transmission rebuild, I don't want to shell out more cash if my car will be a money pit because if I go through with this motor swap I'll junk the car. So please, can anyone give me a list of suggestions as to what I can do to? Side note: I can probably get a warranty on the motor as I did with the transmission