Going to look at a 69 stepsite tomorrow, need tips

[WhiteLX]

I am going to take a look at a 69 C-10 shortbed stepside tomorrow evening. I need some tips on what to look for on it. Previously I had taken my time looking all over, but since I am going to look at it in the dark (bad I know), I need to know some specific areas to watch for. I am taking a big halogen lamp as well as a 4-D Maglite. The seller also said he has big lights, so hopefully there will be enough light.

If the truck is decent I will go back this weekend for a 2nd look.

It is a straight 6 with a 3spd manual transmission that has a floor shifter. I am sure that has been converted, which is something I would have done anyway.

Is there anything specific about the I-6 or stepside bed I should look for?

I'll try to get some pictures of this one too.

Also, what is involved in putting a SBC in place of the I-6? I just happen to have a spare 355 SBC sitting in a bag.