340 T/A head identification

Hi guys, I recently picked up a set of heads at a swap meet that are supposed to be a set of 340 T/A heads. I knew a little bit about them before I bought them, like the casting number and "U" that is casted into them, but they have neither. The do have the pushrod holes drilled correctly though. The guy I bought them from told me they were over the counter performance heads, and they were complete and priced reasonable, so I bought them. I have yet to find a single bit of information on them, and was wondering if anyone has any knowledge about what they are, and what they were used for. My guess is they were used by race teams back in the day, but like I said I really don't know. They have absolutely no porting done, and the valves measure at 2.02/1.60 like they are supposed to. Any info would be appreciated. Thanks, Logan.