Ethan Gueck

I just got my grandpas old international truck that he has always bragged about having a corvette engine in it. As I know nothing about cars and engines I want to know if anyone can tell me how to figure out what this engine is and where it came from. I took some pictures of numbers I found on the engine.
This says E13 5 and is on the front of the engine on driver side. This says 3783244 GM 2 and was on top of the engine toward the fire wall. This says B82 and is right behind the previous set of numbers just shown as you can see in the picture. I'm not sure if this is the date code or if the next one is. This says A299 and is on the back of the engine passenger side. I'm not sure if this is the date code or the previous one is. This says GM 6 3756519 and is on the back of the engine driver side. I couldn't find a partial vin number, but also am not sure where to look. If anyone could tell me what this engine is or anything about it, it would be greatly appreciated.