6 cyl manifold leak

[scott-wisc]

My truck that I recently bought has a massive exhaust leak where the intake and exhaust manifolds meet under the carb. someone packed JB Weld in to fill the gap but it's not holding. Is something missing or are these two parts not meant to go with each other?

Also, where can I identify the CID of the engine? Do I decode the casting number, or is the engine size stated somewhere. A specific location would help as the block has a thick coat of grime.

Thanks, Scott