5.3L G-body Cutlass

[veltboy618]

I am doing a frame off resto on my 1985 Olds Cutlass & I really want to do a little engine upgrade before it gets put back together. I'm not trying to race or anything like that... I just want to get better gas mileage & I think it will look better that the engine I had in it so I have been checking out a lot of sites & reading through a lot of different threads about the 5.3L engine swaps & I want to put one in my cutlass. I found a guy on CL selling one for $700 so I went to check it out yesterday. The guy said he was going to put it in his S-10 but lost interest in the project so it has been sitting for a while but it came out of a wrecked 2002 GMC Sierra with 75K. Is there any way to confirm the mileage & is 75K too much? I have the computer with me. Can I take it somewhere to have it scanned to see what information is stored on it? There is a sticker on the computer with some numbers on it... Can those numbers tell me anything about the engine or the vehicle it came in? I will be picking it up this weekend & bringing it home if I can get this thing checked out. The engine comes with everything & looks pretty good. It has the harness, computer, PS pump, Alt, manifolds, starter, fan & some other things. It also has the drive by cable throttle body. I dont remember if the MAF was there or not. I guess I could just buy another one if it's not. I could not spot any leaks or things like that & I see it still have the tabs on back of the heads so it doesn't look like it has overheated. Here are the pics. Tell me what you think!