I have no idea what they are from
As I stated I removed them from a 69 340 engine, I purchased the engine out of the car, they may have been swapped onto that engine from anything. I do know that they were bolted on to an X head and appear to be the correct exhaust port configuration.
The OP wanted a set of SBM exhaust manifolds all I did was met his request.
Who cares what they are off of as long as they work. That is up to the OP to figure out it's his money.
