Hey guys, I know that this isn't a mechanics forum, but the place feels like home to me and I figured I would ask. I have an 86 gmc 3/4 ton that has started a pretty big oil leak. It's either the rear main or coming from the back of intake. The problem is, I need help identifying the engine. The p.o. told me its a 283 out of a 69 Chevelle, but I do know they stopped making the 283 in 66 or 67. But considering the size I do believe it is a 283. (Before this truck I have been an all Ford guy) But is there any way to tell what engine I have so I get the right gaskets?