Where do you look to find the engine size on a 1986 GMC half ton?

under the hood or Hayes manualthis may be a bad answer but id say either on the underside of the hood or areound the hood latch, and if its scraped off there then maybe check a Hayes manual

either that, or im sure if you look around online, there has to be a vin decoder type thing, that will tell you what engine your truck has, im not sure what number or letter coresponds to what engine it has, but i know somewhere in the vin number, there is a letter or number that tells you what engine you have.