There is a CJ but as far as I know it's not a 351in any form, sounds like some body is try anything to sell it. As far as getting High performance parts for the 335 engines, there is alot more stuff then people know about. You can buy after market cranks, rods and pistons all day long. Intake you have some good choices to and if you can't a 302 boss intake or a cleveland intake then get spacers and mount that on a 351m or 400m motor.
You can also buy longer and stronger push rods, for the tall decks of the 351m and 400m. Everything else from a cleveland should interchange between the motors. Kurt