If it's a replacement block you could have several different internals depending on if it was just a block replacement, a complete '69 short block or any combination of parts. You didn't mention which transmission is going to be used with it, but, check to see which crankshaft it has. If it's a '67 or earlier crank, it will be forged with a small register for the early converters. If it's a '69 crank, it will be a cast iron version with the big hole. If you're going to use a manual transmission, you might want to check to see if the crank has been machined for a pilot bushing. If not, you need to either machine the early crank or cut a bushing down to make it fit properly. If the later crank isn't finished, you can use a later magnum crank pilot BEARING. You're into some fairly serious mods to get that engine in a '62, so, you might want to detail what you're trying to do and what will be needed to make it happen.
