Date coded 340.
Sounds like a nice car!
Are you planning on selling the car? If not, then why go to the hassle when it’s a same for same end result?
If you are planning on selling the car, how much of a premium would you think you’d get for a late 69 block cast (NNM) relative to an early 69 block cast that is also not number matching (NNM)? $250, $500, $1,500, $2,500?
Unless you really want a project to work on to keep you out of the casinos/bars, what other benefits are there?
Presumably when you bought the car you received/negotiated a discount based on it not being numbers matching? So in reality you shouldn‘t be ‘out’ any $$ when you sell the car (assuming you view these cars as an investment).