The letters on the pad at the front of the block (HV) do not match the numbers off the bellhousing (3932388). Check both very carefully. Use a wire brush to brush the letters and numbers to be sure what they are. If you're absolutely certain that they are as you posted, then like Mike said, go by the casting number on the bellhousing. Go with caution before you use the block for a project. It may be a '69 302 block that could fetch good money from someone wanting to restore a Z-28.